Chapter 25 Hormones © 2016 Pearson Education, Inc.

Figure Why Hormones Matter Figure Why hormones matter

Figure a Figure a Why hormones matter (part 1: hypothyroidism)

Figure b Figure b Why hormones matter (part 2: endocrine disruptors)

Figure ba Figure ba Why hormones matter (part 2a: endocrine disruptors, male tadpole)

Figure bb Figure bb Why hormones matter (part 2b: endocrine disruptors, female frog)

Figure c Figure c Why hormones matter (part 3: power posing)

Biology and Society: Should Steroids Be Allowed?
Anabolic steroids, which are known to enhance athletic performance, were banned from Major League Baseball (MLB) in 2001. Nevertheless, the sport has been plagued with scandals of anabolic steroid abuse ever since. In 2013, 13 MLB players were suspended from playing for 50 games or more after being linked to a clinic that sold the banned substances. © 2016 Pearson Education, Inc. 8

Chapter Thread: Steroid Abuse
Figure Chapter Thread: Steroid Abuse Figure Steroid abuse: admitting to steroid use

Steroids are hormones, chemical signals that help regulate body functions, and everyone’s body naturally produces them. Anabolic steroids, are synthetic hormones that mimic the male sex-hormone testosterone. Large doses of synthetic testosterone can increase muscle mass and improve athletic performance, such as the ability of a baseball player to hit a home run. © 2016 Pearson Education, Inc. 10

Hormones: An Overview The cells of your body are constantly communicating with one another through chemical and electrical signals and by traveling by way of two major organ systems: the endocrine system and the nervous system. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 12

Hormones: An Overview The endocrine system is a group of interacting glands and tissues throughout the animal body that produce and secrete chemicals to initiate and maintain body functions. Chemical signals called hormones are released by endocrine cells and carried to all locations in the body, usually via the blood. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 13

Hormones: An Overview Figure 25.1 shows the release of hormone molecules from an endocrine cell. The circulatory system carries hormones throughout the body, but a hormone can only bind to a target cell with receptors for that specific hormone. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 14

Adrenal glands (glands of the endocrine system,
Figure 25.1 Endocrine cell Nucleus Membrane- enclosed sacs Adrenal glands (glands of the endocrine system, which sit atop the kidneys) Blood vessel Hormone molecules Target cell Receptor protein Figure 25.1 Hormone secretion from an endocrine cell

Hormones: An Overview Because hormones reach all parts of the body, the endocrine system is especially important in controlling whole-body activities. Hormones trigger changes in target cells in different ways, depending on whether the hormone is water-soluble or lipid-soluble: Water-soluble hormones trigger responses without entering the cell. Lipid-soluble hormones trigger responses after entering the cell. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 16

Hormones: An Overview Water-soluble hormones cannot pass through the phospholipid bilayer of the plasma membrane, but they can bring about cellular changes without entering their target cells. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 17

Animation: Water-Soluble Hormone
© 2016 Pearson Education, Inc.

1 Water- soluble hormone Receptor protein Target cell Plasma membrane
Figure 25.2-s1 Water- soluble hormone Receptor protein 1 Target cell Plasma membrane Nucleus Figure 25.2-s1 A hormone that binds to a plasma membrane receptor (step 1)

1 2 Water- soluble hormone Receptor protein Target cell Plasma
Figure 25.2-s2 Water- soluble hormone Receptor protein 1 Target cell 2 Plasma membrane Signal transduction pathway Relay molecules Nucleus Figure 25.2-s2 A hormone that binds to a plasma membrane receptor (step 2)

1 2 3 Water- soluble hormone Receptor protein Target cell Plasma
Figure 25.2-s3 Water- soluble hormone Receptor protein 1 Target cell 2 Plasma membrane Signal transduction pathway Relay molecules Cytoplasmic response or 3 Nucleus Gene regulation Figure 25.2-s3 A hormone that binds to a plasma membrane receptor (step 3)

Hormones: An Overview In contrast, lipid-soluble hormones pass through the phospholipid bilayer and trigger responses by binding to receptors inside the target cell. Steroid hormones—including natural ones such as the sex hormones (testosterone and estrogen) as well as artificial anabolic steroids—work in this manner. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 22

Animation: Lipid-Soluble Hormone
© 2016 Pearson Education, Inc.

1 Lipid- soluble hormone Target Plasma cell membrane Nucleus
Figure 25.3-s1 Lipid- soluble hormone 1 Target cell Plasma membrane Nucleus Figure 25.3-s1 A hormone that binds to an intracellular receptor (step 1)

1 2 Lipid- soluble hormone Target Plasma cell membrane Receptor
Figure 25.3-s2 Lipid- soluble hormone 1 Target cell Plasma membrane 2 Receptor protein Nucleus Figure 25.3-s2 A hormone that binds to an intracellular receptor (step 2)

1 2 3 Lipid- soluble hormone Target Plasma cell membrane Receptor
Figure 25.3-s3 Lipid- soluble hormone 1 Target cell Plasma membrane 2 Receptor protein 3 Nucleus Hormone- receptor complex Figure 25.3-s3 A hormone that binds to an intracellular receptor (step 3)

1 2 3 4 Lipid- soluble hormone Target Plasma cell membrane Receptor
Figure 25.3-s4 Lipid- soluble hormone 1 Target cell Plasma membrane 2 Receptor protein 3 Nucleus Hormone- receptor complex 4 Gene regulation Figure 25.3-s4 A hormone that binds to an intracellular receptor (step 4)

Hormones: An Overview Animals have many hormones in common, a result of shared ancestry. Yet over the course of evolution, the functions of a given hormone have diverged between species. For example, thyroid hormone plays a role in regulating metabolism in many vertebrates, yet stimulates metamorphosis in frogs (the process in which tadpoles become adults). © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies on a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been addressed previously or recently in your course, consider a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways to coordinate activities in our world. Endocrine glands send out hormones in the body similar to the way that radio stations and satellites broadcast signals over the Earth. Only certain cells with the right receptors are affected by a specific hormone, just as only a radio tuned to a particular station’s frequency (like target cells) will receive a specific radio signal. The nervous system provides direct connections between the sender and receiver, much more like a land-based telephone call. These analogies might help establish the basic mechanisms of the endocrine system and avoid early confusion. Teaching Tips 1. The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for shorter duration than the endocrine system. 2. Consider this analogy to compare the two mechanisms by which hormones trigger changes in target cells. Imagine that a house is like a cell. Ringing the doorbell and having someone answer it is like using a signal transduction pathway. Pushing the doorbell, like a hormone binding to plasma membrane receptors, causes an internal change. The second mechanism, using steroid hormones, is like walking up to the house, opening the door, and walking inside to speak to a friend. Here the signal (the person) passes through the surface and interacts deep within the home to directly communicate a message. 28

The Human Endocrine System
Hormones are made and secreted mainly by organs called endocrine glands. The human endocrine system consists of about a dozen major glands. Some of these organs, such as the thyroid and pituitary glands, are endocrine specialists and their primary function is to secrete hormones into the blood. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 29

Other organs, for example, the stomach and the pancreas of the digestive system, are primarily nonendocrine but have some cells that secrete hormones. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 30

Hormones have a wide range of target cells and effects. Figure 25.4 shows the locations of some of the major human endocrine glands. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 31

Hypothalamus Thyroid gland Pituitary gland Adrenal glands Pancreas
Figure 25.4 Hypothalamus Thyroid gland Pituitary gland Adrenal glands Pancreas Ovaries (in females) Testes (in males) Figure 25.4 Endocrine glands in humans

Information Flow: The Hypothalamus and Pituitary Gland
is a gland in the brain, acts as the main control center of the endocrine system, receives information from nerves about the internal condition of the body and the external environment, and responds by sending out appropriate nervous or endocrine signals. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 33

Brain Hypothalamus Posterior pituitary Anterior pituitary Bone
Figure 25.5 Brain Hypothalamus Posterior pituitary Anterior pituitary Bone Figure 25.5 Location of the hypothalamus and pituitary

The pituitary gland is a pea-sized structure that hangs below the hypothalamus, responds to signals from the hypothalamus, and secretes hormones that influence numerous body functions. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 35

Hypothalamus Pituitary gland Hormones
Figure 25.6 Information about internal conditions and external environment received by the Hypothalamus Signals sent to posterior and anterior lobes of the Pituitary gland Information flow Hormones that affect body functions secreted by the pituitary gland Figure 25.6 Master control exerted by the hypothalamus

The flow of information to and from the hypothalamus is illustrated when we consider how the endocrine system maintains homeostasis. As you see in Figure 25.7, when the hypothalamus receives information that the body tissues are dehydrated, it makes antidiuretic hormone (ADH), which is stored and released by the pituitary gland. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 37

(receives information reabsorption, decreases prevents dehydration.)
Figure 25.7 Hypothalamus (receives information when tissues are dehydrated) ADH (antidiuretic hormone) Posterior pituitary Anterior pituitary Blood vessel ADH Kidneys (ADH increases water reabsorption, decreases urine output, and prevents dehydration.) Figure 25.7 ADH and osmoregulation

ADH signals kidney cells to reabsorb more water so that less urine is produced and serious dehydration is prevented. As an individual rehydrates, the hypothalamus slows the release of ADH from the pituitary and the kidneys increase the output of urine. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 39

The pituitary gland consists of two distinct parts. The posterior pituitary is an extension of the hypothalamus, stores hormones, and secretes hormones made in the hypothalamus. Two hormones are released by the posterior pituitary: ADH and oxytocin. The anterior pituitary synthesizes and secretes its own hormones directly into the blood. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 40

The hypothalamus exerts control over the anterior pituitary by secreting two kinds of hormones into short blood vessels that connect the two glands. Releasing hormones stimulate the anterior pituitary to secrete specific hormones. Inhibiting hormones induce the anterior pituitary to stop secreting specific hormones. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 41

One of several anterior pituitary secretions is human growth hormone (HGH), which promotes development and enlargement of all parts of the body and can lead to gigantism, if too much HGH is produced in a very young person, or dwarfism, if too little HGH is produced. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 42

Gigantism Average height Pituitary Height in feet dwarfism 8 7 6 5 4 3
Figure 25.8 8 Gigantism 7 6 Average height 5 Pituitary dwarfism Height in feet 4 3 2 1 Figure 25.8 Pituitary growth hormone disorders

Figure Gigantism Figure Pituitary growth hormone disorders (part 1: gigantism)

Pituitary dwarfism Figure 25.8-2
Figure Pituitary growth hormone disorders (part 2: pituitary dwarfism)

The Thyroid Regulates Metabolism and Development
The thyroid gland is located in the front of your neck and produces thyroid hormone in response to thyroid stimulating hormone (TSH) released from the anterior pituitary. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 46

Affects metabolic rate, blood pressure,
Figure 25.9 Anterior pituitary (directed by the hypothalamus) Thyroid stimulating hormone (TSH) Thyroid hormone inhibits TSH release. Thyroid gland Thyroid hormone Affects metabolic rate, blood pressure, heart rate, and tolerance to cold Figure 25.9 Thyroid hormone production

Thyroid hormone affects many functions of the body including metabolic rate (the amount of energy expended over a period of time), heart rate, blood pressure, tolerance to cold, and the development and maturation of bone and nerve cells in children. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 48

Disease or environmental toxins are causes of hypothyroidism. Hashimoto’s disease is an autoimmune disorder in which the body’s immune system attacks cells of the thyroid—interfering with its ability to make thyroid hormone. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 49

Environmental toxins that adversely affect the endocrine system, termed endocrine disruptors, are commonly found in pesticides and plastic containers. For example, BPA (bisphenol A) is an endocrine disruptor found in some plastic water bottles. A growing body of evidence links particular endocrine disruptors to thyroid disease in animals. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 50

Hyperthyroidism (overproduction of thyroid hormone) is characterized by weight loss, high blood pressure, rapid heart rate, and increased sensitivity to heat (profuse sweating). © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 51

Whereas a low dose of radioactive iodine treats disease, a high dose of it can be deadly. Nuclear fallout often produces dangerous plumes of radioactive iodine that enter the air, water, and food supply. When radioactive iodine accumulates in the thyroid, the risk of thyroid cancer increases, especially in young children. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 52

To help protect the thyroid, a stable form of iodine, potassium iodide (KI), is taken in pill form before or immediately after exposure to nuclear fallout. This treatment “fills up” the thyroid with stable iodine so that the thyroid cannot take up the harmful radioactive iodine. These pills are sometimes advertised to consumers as a necessity for “doomsday” preparation. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 53

The Pancreas Regulates Blood Glucose
The pancreas secretes two hormones, insulin and glucagon, that play important roles in managing the body’s energy supplies. As shown in Figure 25.10, insulin and glucagon are antagonistic hormones, countering each other in a feedback circuit that precisely manages the level of glucose in the blood. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 54

Normal blood glucose level
Figure 25.10 Body cells take up glucose Insulin 2 Pancreas releases insulin 3 Liver stores glucose as glycogen Blood glucose level falls 1 Stimulus: Rising blood glucose Glucose level Homeostasis: Normal blood glucose level Stimulus: Declining blood glucose Glucose level 4 6 Blood glucose level rises Pancreas releases glucagon 5 Liver breaks down glycogen Glucagon Figure Glucose homeostasis

Figure Body cells take up glucose Insulin 2 Pancreas releases insulin 3 Liver stores glucose as glycogen Blood glucose level falls 1 Stimulus: Rising blood glucose Glucose level Homeostasis: Normal blood glucose level Figure Glucose homeostasis (part 1: rising blood glucose)

Figure Homeostasis: Normal blood glucose level Stimulus: Declining blood glucose Glucose level 4 6 Blood glucose level rises Pancreas releases glucagon 5 Liver breaks down glycogen Glucagon Figure Glucose homeostasis (part 2: declining blood glucose)

Diabetes mellitus is a serious hormonal disease that affects about 1 in 12 Americans; millions of them don’t even know they are ill. If current trends continue, 1 in 3 Americans will be affected by 2050. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 58

In diabetes, body cells are unable to absorb glucose from the blood, either because there is not enough insulin in the blood (as in type 1, or insulin- dependent, diabetes) or because the target cells do not respond normally to the insulin in the blood (as in type 2, or non-insulin-dependent, diabetes). A third type of diabetes, called gestational diabetes, can affect any woman during pregnancy, even one who has never shown symptoms of diabetes before. Of those Americans who have diabetes, more than 90% have type 2. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 59

In a person with diabetes, a lack of insulin or the inability of cells to access it causes glucose to build up in the blood. Diabetics measure their blood glucose routinely throughout the day. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 60

Figure 25.11 Figure Measuring blood glucose

Figure Figure Measuring blood glucose (part 1: glucose meter)

Figure Figure Measuring blood glucose (part 2: insulin pump)

There are treatments for diabetes but no cure. Type 1 patients require regular injections of insulin. Type 2 is almost always associated with being overweight and underactive, although whether obesity causes diabetes (and if so, how) remains unknown. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 64

Low income appears to be a factor in developing type 2 diabetes, and low-income diabetics often suffer greater complications from the disease. Scientists from the University of California, San Francisco, hypothesized that diabetics with low income would have more health problems at the end of a calendar month (compared to the beginning) when they have little to no money for food. As you see in Figure 25.12, the data show a strong association between hypoglycemia and the end of the calendar month for low-income but not high- income patients. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 65

hypoglycemia per 100,000 admissions Number of people admitted with
Figure 25.12 300 290 300 260 240 200 200 200 190 200 hypoglycemia per 100,000 admissions Number of people admitted with 100 1 2 3 4 Weeks of a calendar month Low income High income Figure Rate of hospital admissions for hypoglycemia in low- and high-income patients

The Adrenal Glands Respond to Stress
Epinephrine (also called adrenaline) and norepinephrine are “fight-or-flight” hormones, are water-soluble hormones, and can be activated in seconds and last for minutes or hours. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 67

The adrenal glands are paired structures resting atop each kidney. Each adrenal gland consists of two glands: the central adrenal medulla and the outer adrenal cortex. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 68

The “fight-or-fight” hormones are secreted by the adrenal medulla. A stressful stimulus, such as a door slamming unexpectedly, activates nerve cells in the hypothalamus to send signals that stimulate the adrenal medulla to secrete epinephrine and norepinephrine into the blood. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 69

1 3 4 5 2 Adrenal medulla Adrenal gland Adrenal cortex Kidney
Figure 25.13 Adrenal medulla Adrenal gland Adrenal cortex Kidney Hypothalamus 1 Nerve signals 3 Releasing hormone Nerve cell Anterior pituitary Spinal cord (cross section) Blood vessel ACTH Nerve cell 4 Adrenal medulla (ACTH) Adrenal cortex 5 Epinephrine and norepinephrine 2 Corticosteroids Short-term stress response Long-term stress response • Glycogen broken down to glucose; increased blood glucose • Increased blood pressure, breathing rate, heart rate, and metabolic rate • Change in blood flow patterns, leading to increased alertness and decreased digestive activity • Proteins and fats broken down and converted to glucose, leading to increased blood glucose • Immune system may be suppressed Figure How the adrenal glands control our response to stress

1 2 Nerve signals Nerve cell Spinal cord (cross section) Nerve cell
Figure 1 Nerve signals Nerve cell Spinal cord (cross section) Nerve cell Adrenal medulla Epinephrine and norepinephrine 2 Short-term stress response Figure How the adrenal glands control our response to stress (part 1: short-term stress response)

3 4 5 Hypothalamus Releasing hormone Anterior pituitary Blood vessel
Figure Hypothalamus 3 Releasing hormone Anterior pituitary Blood vessel ACTH 4 Adrenal cortex (ACTH) 5 Corticosteroids Long-term stress response Figure How the adrenal glands control our response to stress (part 2: long-term stress response)

Adrenal medulla Adrenal gland Adrenal cortex Kidney Figure 25.13-3
Figure How the adrenal glands control our response to stress (part 3: location of adrenal gland)

Short-term stress response
Figure Short-term stress response • Glycogen broken down to glucose; increased blood glucose • Increased blood pressure, breathing rate, heart rate, and metabolic rate • Change in blood flow patterns, leading to increased alertness and decreased digestive activity Long-term stress response • Proteins and fats broken down and converted to glucose, leading to increased blood glucose • Immune system may be suppressed Figure How the adrenal glands control our response to stress (part 4: stress responses lists)

In contrast to epinephrine and norepinephrine (secreted by the adrenal medulla), hormones secreted by the adrenal cortex can provide a slower, longer-lasting response to stress that can last for hours or days, say in preparation for a job interview. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 75

The hypothalamus secretes a releasing hormone that stimulates the pituitary to secrete a hormone called ACTH (adrenocorticotropic hormone). ACTH stimulates cells of the adrenal cortex to synthesize and secrete a family of lipid-soluble steroid hormones called corticosteroids, which includes the hormone cortisol. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 76

Cortisol helps promote the synthesis of glucose from non-carbohydrates, such as proteins and fats. The energy is needed when the body is coping with stressful situations. As cortisol increases energy for vital functions, it can suppress less immediate functions, such as the body’s immune system. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 77

Can you affect the balance of your stress hormones? One study that concludes you can is well known in the business community. Researchers from Columbia and Harvard business schools examined how hormones were affected when individuals posed for 2 minutes in positions of power. They found that, on average, 17 minutes after power posing, individuals had a decrease in the stress hormone cortisol and an increase in the sex hormone testosterone. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 78

The Gonads Produce Sex Hormones
Women and men produce the same sex hormones. The gonads, or sex glands (ovaries in the female and testes in the male), produce three categories of sex hormones: estrogens, progestin, and androgens. The proportions of these hormones are what differentiate the sexes. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 79

The sex hormones are steroid hormones (lipid- soluble) that are secreted under the direction of the hypothalamus and anterior pituitary gland. Growth and development are affected by sex hormones, as are the reproductive cycle and sexual behavior. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 80

Estrogens and progestins are found in higher concentrations in women than in men. Estrogens maintain the female reproductive system and promote the development of specific female features, such as breasts and wider hips. Progestins, such as progesterone, are primarily involved in preparing the uterus to support a developing embryo. Both hormones are critical to the female menstrual cycle. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 81

Control by hypothalamus (d) Levels of ovarian hormones in blood
Figure 26.9 (a) Control by hypothalamus (d) Levels of ovarian hormones in blood Inhibited by combination of estrogen and progesterone 3 Peak causes LH surge Hypothalamus 6 Stimulated by high levels of estrogen Releasing hormone 7 Anterior pituitary Estrogen 7 Progesterone 1 FSH LH Low levels trigger menstruation Progesterone and estrogen promote thickening of endometrium (b) Levels of pituitary hormones in blood 4 Peak triggers ovulation and corpus luteum formation (e) Menstrual cycle Endometrium LH FSH 2 FSH stimulates follicle to grow LH peak triggers ovulation 5 10 14 15 20 25 28 Days (c) Ovarian cycle 5 Menstruation Growing follicle Corpus luteum Degenerating corpus luteum Mature follicle Ovulation Estrogen secreted by growing follicle Progesterone and estrogen secreted by remnant of follicle 5 10 14 15 20 25 28 Days Figure 26.9 The reproductive cycle of the human female

Control by hypothalamus
Figure (a) Control by hypothalamus Inhibited by combination of estrogen and progesterone Hypothalamus Stimulated by high levels of estrogen Releasing hormone Anterior pituitary 1 FSH LH (b) Levels of pituitary hormones in blood 4 Peak triggers ovulation and corpus luteum formation LH FSH 2 FSH stimulates follicle to grow LH peak triggers ovulation 5 10 14 15 20 25 28 Days Figure The reproductive cycle of the human female (part 1: hypothalamus and pituitary hormones)

(b) Levels of pituitary hormones in blood (c) Ovarian cycle 4
Figure (b) Levels of pituitary hormones in blood 4 Peak triggers ovulation and corpus luteum formation LH FSH 2 FSH stimulates follicle to grow LH peak triggers ovulation (c) Ovarian cycle 5 Corpus luteum Degenerating corpus luteum Growing follicle Mature follicle Ovulation Estrogen secreted by growing follicle Progesterone and estrogen secreted by remnant of follicle 5 10 14 15 20 25 28 Days Figure The reproductive cycle of the human female (part 2: pituitary hormones and ovarian cycle)

(c) Ovarian cycle (d) Levels of ovarian hormones in blood 5 Corpus
Figure (c) Ovarian cycle 5 Corpus luteum Degenerating corpus luteum Growing follicle Mature follicle Ovulation Estrogen secreted by growing follicle Progesterone and estrogen secreted by remnant of follicle (d) Levels of ovarian hormones in blood Peak causes 3 LH surge 6 7 Estrogen Progesterone Low levels trigger menstruation Progesterone and estrogen promote thickening of endometrium 5 10 14 15 20 25 28 Days Figure The reproductive cycle of the human female (part 3: ovarian cycle and ovarian hormones)

(d) Levels of ovarian hormones in blood (e) Menstrual cycle
Figure (d) Levels of ovarian hormones in blood Peak causes 3 LH surge 6 7 Estrogen Progesterone Low levels trigger menstruation Progesterone and estrogen promote thickening of endometrium (e) Menstrual cycle Endometrium 5 10 14 15 20 25 28 Days Menstruation Figure The reproductive cycle of the human female (part 4: ovarian hormones and menstrual cycle)

Men have high levels of androgens (the main one being testosterone), which stimulate the development and maintenance of the male reproductive system. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 87

Endocrine disruptors affect the thyroid, but others affect reproductive function by altering the balance of sex hormones. In one study, scientists examined the effects of an endocrine disruptor on frogs. They raised male frogs in the absence (control) or presence of a chemical found in weed-killers called atrazine. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 88

When male frogs reached adulthood, they found that atrazine-exposed males were far less successful at mating behaviors and had a lower testosterone level. Furthermore, 10% underwent complete sex reversal. They became females capable of producing eggs! © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 89

Structure/Function: Mimicking Sex Hormones
Chemicals that affect the balance of sex hormones are not always detrimental. A drug used in breast cancer treatment decreases estrogen’s effects, and synthetic hormones are useful for boosting function in individuals deficient in particular hormones. These chemicals have similarities in structure and function to the natural hormones they mimic. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 90

Approximately 70% of all breast cancers rely on estrogen to grow and divide, so inhibiting estrogen binding or its effects is a successful way to treat many breast cancers. Tamoxifen is one drug that inhibits estrogen. Once in the body, tamoxifen is broken down into molecules that bind to estrogen receptors. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 91

Cell division/ Tumor growth
Figure 25.14 Estrogen Estrogen Breast cancer cell Breast cancer cell Plasma membrane Plasma membrane Nucleus Nucleus Estrogen- receptor complex ER cannot bind estrogen; cell division and tumor growth inhibited. Tamoxifen breakdown product binds ER. Cell division/ Tumor growth Figure Breast cancer drug treatment

As individuals age, sex hormone levels decline. One treatment for the side effects of menopause is synthetic estrogen. Anabolic steroids, artificial hormones that are similar in structure and function to testosterone, are sometimes used to treat the gradual decline of testosterone in men. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 93

The Process of Science: Do ‘Roids Cause Rage?
Observation: Doctors observed an apparent link between abuse of anabolic steroids and violent mood swings. Question: Could scientists measure a relationship between steroids and mood in the lab? © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 94

Hypothesis: The administration of increasing doses of steroids to volunteers would produce measurable changes in behavior. Prediction: Scientists could document mood swings resulting from anabolic steroid injection. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 95

Experiment: Twenty male volunteers between the ages of 18 and 42 who had no history of drug abuse or psychiatric problems were given a placebo drug with no steroids for days 1–3, a low dose of steroids for days 4–6, a high dose of steroids for days 7–9, and then a placebo for days 10–12. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 96

Results: The experiment revealed a significant increase in ratings for hostility, anger, and violent feelings during the high-dose period. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 97

Mood self-ratings 30 25 20 15 10 5 Irritability Anger Violent feelings
Figure 25.15 30 25 20 Mood self-ratings 15 10 5 Irritability Anger Violent feelings Placebo (days 1–3) High dose of steroids (days 7–9) Low dose of steroids (days 4–6) Placebo (days 10–12) Figure The mood-altering effects of anabolic steroids

Evolution Connection: Steroids and Male Aggression
Testosterone and other androgens promote the development and maintenance of the human male reproductive system and play a similar role in all vertebrates. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 99

In addition to determining the male sexual condition, in many vertebrates, androgens are responsible for male vocalizations, and thus the idea that steroid abuse can lead to aggressive behavior may have an evolutionary basis. © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 100

The roles that androgens play among vertebrates illustrate two central aspects of life that result from Darwinian evolution: the unity of life (a consistent effect on the development of the male gonads) and the diversity of life (the variety of secondary effects). © 2016 Pearson Education, Inc. Student Misconceptions and Concerns 1. A central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. 2. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate endocrine organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the benefits and potential risks of human growth hormone injections in the elderly. 2. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. The following website of the National Institute of Health provides additional details: 3. Students might not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. 4. Hypothyroidism produces symptoms that are like turning down the temperature in a home during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence. 5. The use of insulin and glucagon to hold blood sugar levels steady is similar to the use of a furnace and air conditioner in a home to keep temperatures steady. 6. Scientists are exploring the use of pancreatic cell transplants into patients with type 1 diabetes as a new source of insulin. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/ 7. The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling a person experiencing this response to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will more likely reverse the condition. 8. There seems to be no equivalent of menopause in males. Although men experience a steady decline in testosterone production as they age, they can retain the ability to father offspring through at least 80 years of age. 9. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. They can be reached at 10. In humans, differences in the concentrations of sex hormones between the sexes decrease in late adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic. Active Lecture Tips 1. See the Activity Applying Understanding of Female Hormones to Birth Control on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 2. See the Activity Using Diabetes as the Story to Discuss the Secretory Pathway of Proteins on the Instructor Exchange. Visit the Instructor Exchange in the MasteringBiology instructor resource area for a description of this activity. 101

Figure 25.16 Figure Male elephant seals battling for dominance

Figure 25.UN01 Figure 25.UN01 In-text figure, hypothalamus and pituitary, p. 538

Figure 25.UN02 Figure 25.UN02 In-text figure, thyroid, p. 540

Figure 25.UN03 Figure 25.UN03 In-text figure, pancreas, p. 541

Figure 25.UN04 Figure 25.UN04 In-text figure, adrenal glands, p. 543

Figure 25.UN05 Figure 25.UN05 In-text figure, gonads, p. 545

Water- soluble hormone Lipid- soluble hormone Receptor protein
Figure 25.UN06 Water- soluble hormone Lipid- soluble hormone Receptor protein Receptor protein Signal transduction pathway Cytoplasmic response Nucleus Hormone- receptor complex or Nucleus Gene regulation Gene regulation Figure 25.UN06 Summary of key concepts: water- and lipid-soluble hormones

Master control center of the endocrine system
Figure 25.UN07 Brain Hypothalamus: Master control center of the endocrine system Posterior pituitary: Stores and secretes hormones made by hypothalamus Anterior pituitary: Controlled by hypothalamus; produces and secretes its own hormones Blood vessels Figure 25.UN07 Summary of key concepts: hypothalamus and pituitary gland

Normal level of thyroid hormone in blood Thyroid hormone
Figure 25.UN08 Excess level of thyroid hormone in blood Hyperthyroidism releases Normal level of thyroid hormone in blood Thyroid hormone Thyroid Homeostasis Insufficient level of thyroid hormone in blood Hypothyroidism Figure 25.UN08 Summary of key concepts: thyroid

Glucose causes in blood Insulin releases releases causes Pancreas
Figure 25.UN09 Glucose in blood causes Insulin releases releases causes Pancreas Glucose in blood Glucagon Figure 25.UN09 Summary of key concepts: pancreas

Chapter 25 Hormones © 2016 Pearson Education, Inc.

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