Hormones and the Endocrine System Chapter 26 Hormones and the Endocrine System Lecture by Edward J. Zalisko

Introduction: Gender Benders Endocrine disruptors Environmental pollutants Interfere with the action of hormones Some are estrogen mimics in the environment that may produce Demasculinized male alligators Bass with male and female characteristics Decrease in size and functioning of polar bear genitalia Copyright © 2009 Pearson Education, Inc.

Alligator.

Water runoff.

Polar bear.

THE NATURE OF CHEMICAL REGULATION THE NATURE OF CHEMICAL REGULATION Copyright © 2009 Pearson Education, Inc.

26.1 Chemical signals coordinate body functions Hormones Chemical signals Usually carried in the blood Cause specific changes in target cells Secreted by Endocrine glands Neurosecretory cells For the BLAST Animation Signaling: Endocrine, go to Animation and Video Files. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. 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 a shorter duration than the endocrine system. Copyright © 2009 Pearson Education, Inc.

Secretory vesicles Blood vessel Target cell Endocrine cell Hormone Figure 26.1A Hormone from an endocrine cell. Hormone molecules

Blood vessel Neurosecretory cell Target cell Hormone molecules Figure 26.1B Hormone from a neurosecretory cell. Hormone molecules

26.1 Chemical signals coordinate body functions The endocrine system Consists of all hormone-secreting cells Works with nervous system to regulate body activities The nervous system also Communicates Regulates Uses electrical signals via nerve cells Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. 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 a shorter duration than the endocrine system. Copyright © 2009 Pearson Education, Inc.

26.1 Chemical signals coordinate body functions Comparing the endocrine and nervous systems Nervous system reacts faster Endocrine system responses last longer Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. 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 a shorter duration than the endocrine system. Copyright © 2009 Pearson Education, Inc.

Nerve cell Nerve signals Neurotransmitter molecules Nerve cell Figure 26.1C Neurotransmitter from a nerve cell. Nerve cell

26.2 Hormones affect target cells by two main signaling mechanisms Hormone signaling involves three key events Reception Signal Transduction Response Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips 1. The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If 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. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message. Copyright © 2009 Pearson Education, Inc.

26.2 Hormones affect target cells by two main signaling mechanisms Amino-acid-derived hormones Are water-soluble Include proteins, peptides, and amines Bind to plasma-membrane receptors on target cells Initiate a signal transduction pathway For the BLAST Animation Signaling via Steroid Hormones, go to Animation and Video Files. Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips 2. The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If 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. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message. Animation: Water-Soluble Hormone Copyright © 2009 Pearson Education, Inc.

hormone (epinephrine) Receptor 1 protein Target cell Plasma membrane Water-soluble hormone (epinephrine) Receptor protein 1 Target cell Plasma membrane Figure 26.2A A hormone that binds a plasma-membrane receptor.

hormone (epinephrine) Receptor 1 protein Target 2 cell Plasma membrane Water-soluble hormone (epinephrine) Receptor protein 1 Target cell 2 Plasma membrane Signal transduction pathway Relay molecules Figure 26.2A A hormone that binds a plasma-membrane receptor.

(in this example, glycogen breakdown) Water-soluble hormone (epinephrine) Receptor protein 1 Target cell 2 Plasma membrane Signal transduction pathway Relay molecules 3 Figure 26.2A A hormone that binds a plasma-membrane receptor. Glycogen Glucose Cellular response (in this example, glycogen breakdown)

26.2 Hormones affect target cells by two main signaling mechanisms Steroid hormones Nonpolar lipids made from cholesterol Can diffuse through plasma membranes Bind to a receptor protein in the cytoplasm or nucleus Hormone-receptor complex carries out the transduction of the hormonal signal Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips 1. The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If 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. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message. Animation: Lipid-Soluble Hormone Copyright © 2009 Pearson Education, Inc.

hormone (testosterone) 1 Target cell Nucleus Lipid-soluble Figure 26.2B A hormone that binds an intracellular receptor.

hormone (testosterone) 1 Target cell 2 Receptor protein Nucleus Lipid-soluble hormone (testosterone) 1 Target cell 2 Receptor protein Nucleus Figure 26.2B A hormone that binds an intracellular receptor.

hormone (testosterone) 1 Target cell 2 Receptor protein 3 Hormone- Lipid-soluble hormone (testosterone) 1 Target cell 2 Receptor protein 3 Hormone- receptor complex Nucleus DNA Figure 26.2B A hormone that binds an intracellular receptor.

activation of a gene and synthesis of new protein Lipid-soluble hormone (testosterone) 1 Target cell 2 Receptor protein 3 Hormone- receptor complex Nucleus DNA 4 Transcription mRNA Figure 26.2B A hormone that binds an intracellular receptor. New protein Cellular response: activation of a gene and synthesis of new protein

THE VERTEBRATE ENDOCRINE SYSTEM THE VERTEBRATE ENDOCRINE SYSTEM Copyright © 2009 Pearson Education, Inc.

26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands The vertebrate endocrine system Consists of more than a dozen glands Secretes more than 50 hormones Student Misconceptions and Concerns 1. Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormonal signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the consequences of human growth hormone injections in the elderly. Copyright © 2009 Pearson Education, Inc.

Hypothalamus Pineal gland Pituitary gland Thyroid gland Thymus Parathyroid glands Thymus Adrenal glands (atop kidneys) Pancreas Figure 26.3 The major endocrine glands in humans. Ovary (female) Testes (male)

26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands Hormones Some have a very narrow range of targets and effects Some have numerous effects on many kinds of target cells Student Misconceptions and Concerns 1. Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormonal signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips 1. Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the consequences of human growth hormone injections in the elderly. Copyright © 2009 Pearson Education, Inc.

Table 26.3 Major Human Endocrine Glands and Some of Their Hormones.

Table 26.3 Major Human Endocrine Glands and Some of Their Hormones.

26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems The hypothalamus Blurs the distinction between endocrine and nervous systems Receives input from nerves about body conditions Responds by sending out appropriate nervous or endocrine signals Uses the pituitary gland to exert master control over the endocrine system Student Misconceptions and Concerns 1. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institutes of Health provide additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. Copyright © 2009 Pearson Education, Inc.

26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems The pituitary gland consists of two parts Posterior pituitary Composed of nervous tissue Stores and secretes oxytocin and ADH Student Misconceptions and Concerns 1. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institutes of Health provide additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. Copyright © 2009 Pearson Education, Inc.

Brain Hypothalamus Posterior pituitary Anterior pituitary (Bone) Figure 26.4A Location of the hypothalamus and pituitary. Anterior pituitary (Bone)

Uterine muscles Mammary glands Hypothalamus Hormone Neurosecretory cell Posterior pituitary Anterior pituitary Blood vessel Figure 26.4B Hormones of the posterior pituitary. Oxytocin ADH Uterine muscles Mammary glands Kidney tubules

26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems Anterior pituitary Synthesizes and secretes hormones that control the activity of other glands Is controlled by the hypothalamus Releasing hormones stimulate the anterior pituitary Inhibiting hormones inhibit the anterior pituitary Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. Student Misconceptions and Concerns 1. The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institutes of Health provide additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. Copyright © 2009 Pearson Education, Inc.

the anterior pituitary Neurosecretory cell Blood vessel Releasing hormones from hypothalamus Endocrine cells of the anterior pituitary Figure 26.4C Hormones of the anterior pituitary. Pituitary hormones TSH ACTH FSH and LH Prolactin (PRL) Growth hormone (GH) Endorphins Thyroid Adrenal cortex Testes or ovaries Mammary glands (in mammals) Entire body Pain receptors in the brain

Inhibition Anterior pituitary Inhibition Thyroid Thyroxine Hypothalamus Inhibition TRH Anterior pituitary Inhibition TSH Figure 26.4D Control of thyroxine secretion. Thyroid Thyroxine

HORMONES AND HOMEOSTASIS HORMONES AND HOMEOSTASIS Copyright © 2009 Pearson Education, Inc.

26.5 The thyroid regulates development and metabolism Thyroid gland hormones Thyroxine (T4) and triiodothyronine (T3) Regulate Metabolism Development Negative feedback Maintain homeostatic levels of T4 and T3 in the blood Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. Hypothyroidism produces symptoms that are like turning down a furnace 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. Copyright © 2009 Pearson Education, Inc.

No inhibition No inhibition No iodine Thyroid grows to form goiter Hypothalamus TRH No inhibition Anterior pituitary TSH Insufficient T4 and T3 produced No iodine Thyroid Figure 26.5B How iodine deficiency causes goiter. Thyroid grows to form goiter

26.5 The thyroid regulates development and metabolism Thyroid imbalance can cause disease Hyperthyroidism Too much T4 and T3 in the blood Leads to high blood pressure, loss of weight, overheating, and irritability Produces Graves’ disease Hypothyroidism Too little T4 and T3 in the blood Leads to low blood pressure, overweight, often cold, lethargy Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. Hypothyroidism produces symptoms that are like turning down a furnace 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. Copyright © 2009 Pearson Education, Inc.

Graves’ disease, a form of hyperthyroidism. Figure 26.5A Graves’ disease, a form of hyperthyroidism.

26.6 Hormones from the thyroid and parathyroids maintain calcium homeostasis Blood calcium level is regulated by a tightly balanced antagonism between Calcitonin from the thyroid Parathyroid hormone (PTH) from the parathyroid glands Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a laboratory incubator to hold temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon. Copyright © 2009 Pearson Education, Inc.

Homeostasis: Normal blood calcium level (about 10 mg/100 mL) 8 7 Calcitonin Thyroid gland releases calcitonin Stimulates Ca2+ deposition in bones Reduces Ca2+ uptake in kidneys 9 6 Blood Ca2+ falls Stimulus: Rising blood Ca2+ level (imbalance) Ca2+ level Homeostasis: Normal blood calcium level (about 10 mg/100 mL) Stimulus: Falling blood Ca2+ level (imbalance) Ca2+ level 1 Blood Ca2+ rises 5 Parathyroid glands release parathyroid hormone (PTH) Figure 26.6 Calcium homeostasis. Stimulates Ca2+ release from bones 2 3 Parathyroid gland PTH Increases Ca2+ uptake in kidneys Active vitamin D Increases Ca2+ uptake in intestines 4

Homeostasis: Normal blood calcium level (about 10 mg/100 mL) Stimulus: Falling blood Ca2+ level (imbalance) Ca2+ level 1 Blood Ca2+ rises 5 Parathyroid glands release parathyroid hormone (PTH) Stimulates Ca2+ release from bones Figure 26.6 Calcium homeostasis. 2 Parathyroid gland 3 PTH Increases Ca2+ uptake in kidneys Active vitamin D Increases Ca2+ uptake in intestines 4

Homeostasis: Normal blood calcium level (about 10 mg/100 mL) 8 7 Calcitonin Thyroid gland releases calcitonin Stimulates Ca2+ deposition in bones Reduces Ca2+ uptake in kidneys 9 6 Stimulus: Rising blood Ca2+ level (imbalance) Blood Ca2+ falls Ca2+ level Figure 26.6 Calcium homeostasis. Homeostasis: Normal blood calcium level (about 10 mg/100 mL) Ca2+ level

26.7 Pancreatic hormones regulate blood glucose levels The pancreas secretes two hormones that control blood glucose Insulin—signals cells to use and store glucose Glucagon—causes cells to release stored glucose into the blood Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a laboratory incubator to hold temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon. 2. 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 http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/. Copyright © 2009 Pearson Education, Inc.

Homeostasis: Normal blood glucose level Body cells take up more glucose Insulin 3 2 Beta cells of pancreas stimulated to release insulin into the blood 4 Blood glucose level declines to a set point; stimulus for insulin release diminishes Liver takes up glucose and stores it as glycogen 1 High blood glucose level Stimulus: Rising blood glucose level (e.g., after eating a carbohydrate-rich meal) Glucose level Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Stimulus: Declining blood glucose level (e.g., after skipping a meal) Glucose level Figure 26.7 Glucose homeostasis. 5 Low blood glucose level Blood glucose level rises to set point; stimulus for glucagon release diminishes 6 Alpha cells of pancreas stimulated to release glucagon into the blood 8 Liver breaks down glycogen and releases glucose to the blood 7 Glucagon

Homeostasis: Normal blood glucose level Body cells take up more glucose Insulin 3 2 Beta cells of pancreas stimulated to release insulin into the blood 4 Blood glucose level declines to a set point; stimulus for insulin release diminishes Liver takes up glucose and stores it as glycogen 1 High blood glucose level Stimulus: Rising blood glucose level (e.g., after eating a carbohydrate-rich meal) Figure 26.7 Glucose homeostasis. Glucose level Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Glucose level

Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Stimulus: Declining blood glucose level (e.g., after skipping a meal) Glucose level 5 Low blood glucose level Blood glucose level rises to set point; stimulus for glucagon release diminishes 6 Alpha cells of pancreas stimulated to release glucagon into the blood Figure 26.7 Glucose homeostasis. 8 Liver breaks down glycogen and releases glucose to the blood 7 Glucagon

26.8 CONNECTION: Diabetes is a common endocrine disorder Diabetes mellitus Results from A lack of insulin or A failure of cells to respond to it Affects about 21 million Americans Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a laboratory incubator to hold temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon. 2. 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 http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/. Copyright © 2009 Pearson Education, Inc.

26.8 CONNECTION: Diabetes is a common endocrine disorder Two common types of diabetes mellitus Type 1 (insulin-dependent) Autoimmune disease Insulin-producing cells destroyed Type 2 (non-insulin-dependent) Deficiency of insulin More commonly, reduced response to insulin More than 90% of diabetics are type 2 Associated with being overweight and underactive Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. 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 http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/. Copyright © 2009 Pearson Education, Inc.

Results of glucose tolerance tests 400 350 300 Diabetic 250 Blood glucose (mg/100 mL) 200 150 Normal 100 Figure 26.8 Results of glucose tolerance tests. 50 1 1 2 3 4 5 2 Hours after glucose ingestion

26.9 The adrenal glands mobilize responses to stress Hormones from the adrenal glands help maintain homeostasis when the body is stressed Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved. Copyright © 2009 Pearson Education, Inc.

26.9 The adrenal glands mobilize responses to stress Nerve signals from the hypothalamus stimulate the adrenal medulla to secrete Epinephrine Norepinephrine These hormones quickly trigger the fight-or-flight responses Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved. Copyright © 2009 Pearson Education, Inc.

26.9 The adrenal glands mobilize responses to stress Adrenocorticotropic hormone (ACTH) from the pituitary causes the adrenal cortex to secrete Glucocorticoids Mineralocorticoids These hormones Boost blood pressure Boost energy in response to long-term stress Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved. Copyright © 2009 Pearson Education, Inc.

Figure 26.9 How the adrenal glands control our responses to stress. medulla Adrenal gland Nerve signals 1 Adrenal cortex Hypothalamus 3 Kidney Releasing hormone Spinal cord (cross section) Nerve cell Anterior pituitary Blood vessel 4 Nerve cell ACTH 5 Adrenal medulla Adrenal cortex ACTH 2 Epinephrine and norepinephrine Mineralocorticoids Glucocorticoids Figure 26.9 How the adrenal glands control our responses to stress. Short-term stress response Long-term stress response 1. Glycogen broken down to glucose; increased blood glucose 2. Increased blood pressure 3. Increased breathing rate 4. Increased metabolic rate 5. Change in blood-flow patterns, leading to increased alertness and decreased digestive and kidney activity Mineralocorticoids Glucocorticoids 1. Retention of sodium ions and water by kidneys 1. Proteins and fats broken down and converted to glucose, leading to increased blood glucose 2. Increased blood volume and blood pressure 2. Immune system may be suppressed

Short-term stress response Long-term stress response Adrenal medulla Adrenal gland Adrenal cortex Kidney Stress Nerve signals 1 Hypothalamus 3 Releasing hormone Spinal cord (cross section) Nerve cell Anterior pituitary Blood vessel 4 Nerve cell ACTH Figure 26.9 How the adrenal glands control our responses to stress. 5 Adrenal medulla Adrenal cortex ACTH 2 Epinephrine and norepinephrine Mineralocorticoids Glucocorticoids Short-term stress response Long-term stress response

Short-term stress response 1. Glycogen broken down to glucose; increased blood glucose 2. Increased blood pressure 3. Increased breathing rate 4. Increased metabolic rate 5. Change in blood-flow patterns, leading to increased alertness and decreased digestive and kidney activity Figure 26.9 How the adrenal glands control our responses to stress.

Long-term stress response Mineralocorticoids Glucocorticoids 1. Retention of sodium ions and water by kidneys 1. Proteins and fats broken down and converted to glucose, leading to increased blood glucose 2. Increased blood volume and blood pressure Figure 26.9 How the adrenal glands control our responses to stress. 2. Immune system may be suppressed

26.10 The gonads secrete sex hormones Steroid sex hormones Include estrogens, progestins, and androgens Produced by the gonads in response to signals from Hypothalamus Pituitary Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. There seems to be no equivalent of menopause in human 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. 2. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. Their website is www.menopause.org. Copyright © 2009 Pearson Education, Inc.

26.10 The gonads secrete sex hormones Estrogens and progestins Stimulate the development of female characteristics Maintain the female reproductive system Androgens Such as testosterone Trigger the development of male characteristics Androgens Such as testosterone Trigger the development of male characteristics Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. There seems to be no equivalent of menopause in human 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. 2. The North American Menopause Society is a scientific nonprofit organization that may be a useful reference for related questions. Their website is www.menopause.org. Copyright © 2009 Pearson Education, Inc.

Male elephant seals in combat Figure 26.10 Male elephant seals in combat.

26.11 EVOLUTION CONNECTION: A single hormone can perform a variety of functions in different animals Prolactin in humans Stimulates mammary glands to grow and produce milk during late pregnancy Suckling by a newborn stimulates further release of prolactin High prolactin during nursing inhibits ovulation Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. The shifting functions of prolactin reflect the kind of “remodeling” frequently found in evolution. Typically, new structures and functions result from modifications of ancestral structures and functions. In this case, as reproductive strategies evolved, the functional significance of prolactin was remodeled. Copyright © 2009 Pearson Education, Inc.

Figure 26.11 Suckling promotes prolactin production.

26.11 EVOLUTION CONNECTION: A single hormone can perform a variety of functions in different animals Prolactin Nonhuman mammals—stimulates nest building Birds—regulates fat metabolism and reproduction Amphibians—movement to water Fish—migration between salt and fresh water The shifting functions of prolactin reflect the remodeling nature of evolution. Typically, new structures and functions result from modifications of ancestral structures and functions. As reproductive strategies evolved, the functional significance of prolactin was remodeled. Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate 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. 2. As the section title indicates, 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. Teaching Tips 1. The shifting functions of prolactin reflect the kind of “remodeling” frequently found in evolution. Typically, new structures and functions result from modifications of ancestral structures and functions. In this case, as reproductive strategies evolved, the functional significance of prolactin was remodeled. Copyright © 2009 Pearson Education, Inc.

To Review… Water- Lipid- soluble soluble hormone hormone Receptor protein Receptor protein Hormone- receptor complex Signal transduction pathway DNA mRNA To Review… Cellular response New protein

To Review… Brain Hypothalamus: Master control center of the endocrine system Anterior pituitary: Composed of endocrine tissue; controlled by hypothalamus; produces and secretes its own hormones Posterior pituitary: Composed of nervous tissue; stores and secretes hormones made by hypothalamus To Review…

1. thyroxine 2. epinephrine 3. androgens 4. insulin 5. melatonin 6. FSH 7. PTH 8. ADH Pineal gland Testes Parathyroid gland Adrenal medulla Pancreas Hypothalamus Anterior pituitary Thyroid gland a. lowers blood glucose b. stimulates ovaries c. triggers fight-or-flight d. promotes male traits e. regulates metabolism f. related to daily rhythm g. raises blood calcium levels h. boosts water retention

You should now be able to Explain how endocrine disruptors are causing environmental problems Compare the mechanisms and functions of the endocrine and nervous systems Distinguish between the two major classes of vertebrate hormones Describe the different types and functions of vertebrate endocrine organs Copyright © 2009 Pearson Education, Inc.

You should now be able to Describe the interrelationships between the hypothalamus and pituitary glands Describe the functions of the thyroid and parathyroid glands Explain how insulin and glucagon manage blood glucose levels Describe the causes and symptoms of types 1 and 2 diabetes Copyright © 2009 Pearson Education, Inc.

You should now be able to Compare the functions of the adrenal gland hormones Describe the three major types of sex hormones and their functions Describe the diverse functions of prolactin in vertebrate groups Copyright © 2009 Pearson Education, Inc.