End Show Slide 1 of 44 Copyright Pearson Prentice Hall Biology Chapter 39 The Endocrine System Chapter 39 The Endocrine System

End Show Slide 2 of 44 Copyright Pearson Prentice Hall What is the function of the endocrine system? To release hormones, which send messages throughout the body via the blood stream.

End Show Slide 3 of 44 Copyright Pearson Prentice Hall What are hormones? Chemicals made & released in one part of the body that affect the cells in OTHER parts of the body. Organs called GLANDS make hormones

End Show Slide 4 of 44 Copyright Pearson Prentice Hall What do hormones do? Hormones bind to specific receptors on their TARGET cells. This changes the activity of the target cells. The effect can last from minutes to days.

End Show Slide 5 of 44 Copyright Pearson Prentice Hall 39-1 Cells that have receptors for a particular hormone are called a.nerve cells. b.target cells. c.exocrine cells. d.endocrine cells.

End Show Slide 6 of 44 Copyright Pearson Prentice Hall 39-1 Chemicals that travel through the bloodstream and affect the activities of other cells are known as a.hormones. b.receptors. c.enzymes. d.messengers.

End Show 39-1 The Endocrine System Slide 7 of 44 Copyright Pearson Prentice Hall Glands Hypothalamus The hypothalamus makes hormones that control the pituitary gland. In addition, the hypothalamus makes hormones that are stored in the pituitary gland. DO NOT WRITE ANYTHING. JUST READ

End Show 39-1 The Endocrine System Slide 8 of 44 Copyright Pearson Prentice Hall Glands Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands.

End Show 39-1 The Endocrine System Slide 9 of 44 Copyright Pearson Prentice Hall Glands Parathyroid glands The parathyroid glands release parathyroid hormone, which regulates the level of calcium in the blood.

End Show 39-1 The Endocrine System Slide 10 of 44 Copyright Pearson Prentice Hall Glands Thymus During childhood, the thymus releases thymosin, which stimulates T cell development and proper immune response. This is important. Write it down.

End Show 39-1 The Endocrine System Slide 11 of 44 Copyright Pearson Prentice Hall Glands Adrenal glands The adrenal glands release adrenaline and norepinephrine, which help the body respond to stress. (Fight or flight response) Know this one.

End Show 39-1 The Endocrine System Slide 12 of 44 Copyright Pearson Prentice Hall Glands Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics.

End Show 39-1 The Endocrine System Slide 13 of 44 Copyright Pearson Prentice Hall Glands Ovary Ovaries produce estrogen and progesterone. Estrogen is required for the development of female secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg.

End Show 39-1 The Endocrine System Slide 14 of 44 Copyright Pearson Prentice Hall Glands Pancreas The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood.

End Show 39-1 The Endocrine System Slide 15 of 44 Copyright Pearson Prentice Hall Glands Thyroid The thyroid produces thyroxine, which regulates metabolism throughout the body.

End Show 39-1 The Endocrine System Slide 16 of 44 Copyright Pearson Prentice Hall Glands Pineal gland The pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles.

End Show 39-1 The Endocrine System Slide 17 of 44 Copyright Pearson Prentice Hall How are hormones classified? Some are STEROID hormones made from a lipid (fat) called cholesterol Steroid hormones can cross cell membranes easily.

End Show Slide 18 of The Endocrine System Copyright Pearson Prentice Hall The Endocrine System Steroid Hormone Action Hormone-receptor complex: notice this directly affects gene expression. Nucleus DNA mRNA Protein synthesis Altered cellular function Receptor Steroid hormone

End Show Slide 19 of The Endocrine System Copyright Pearson Prentice Hall The Endocrine System A steroid hormone enters a cell directly across its membrane. It binds to a receptor to form a hormone- receptor complex. Steroid hormone Receptor Hormone-receptor complex

End Show Slide 20 of The Endocrine System Copyright Pearson Prentice Hall The Endocrine System The hormone-receptor complex enters the nucleus, where it binds to a DNA control sequence. Binding initiates transcription of genes to mRNA. Nucleus DNA mRNA

End Show Slide 21 of The Endocrine System Copyright Pearson Prentice Hall The Endocrine System mRNA moves into the cytoplasm to direct protein synthesis. Protein synthesis Altered cellular function

End Show 39-1 The Endocrine System Slide 22 of 44 Copyright Pearson Prentice Hall Hormone Action How are hormones classified? There are also nonsteroid hormones which include proteins, small peptides and modified amino acids. Nonsteroid hormones CANNOT pass through the cell membrane.

End Show 39-1 The Endocrine System Slide 23 of 44 Copyright Pearson Prentice Hall The Endocrine System A nonsteroid hormone binds to receptors ON THE CELL MEMBRANE. This activates an enzyme on the inside of the membrane. Nonsteroid hormone (first messenger)

End Show 39-1 The Endocrine System Slide 24 of 44 Copyright Pearson Prentice Hall The Endocrine System This enzyme activates secondary messengers that carry the message of the hormone inside the cell. These messengers activate and inhibit many cell activities. ATP cAMP (second messenger) Enzyme activities Altered cellular function

End Show 39-1 The Endocrine System Slide 25 of 44 Copyright Pearson Prentice Hall How does the endocrine system maintain homeostasis? The endocrine system is regulated by FEEDBACK mechanisms that function to maintain homeostasis.

End Show 39-1 The Endocrine System Slide 26 of 44 Copyright Pearson Prentice Hall Control of the Endocrine System What is an example of feedback regulation The control of the metabolic rate of your cells. Thyroxine (made by thyroid gland) increases metabolic rate. Probably affects ALL cells of the body! Important for growth & development. Thyroxine (made by thyroid gland) increases metabolic rate. Probably affects ALL cells of the body! Important for growth & development.

End Show Slide 27 of 44 Copyright Pearson Prentice Hall Problems: 1. How will the body know it should make more thyroxine? Problems: 1. How will the body know it should make more thyroxine? 2. How will it know when it has made enough thyroxine?

End Show 39-1 The Endocrine System Slide 28 of 44 Copyright Pearson Prentice Hall Control of the Endocrine System If thyroxine is low, the hypothalamus secretes thyrotropin-releasing hormone (TRH), which stimulates the anterior pituitary to secrete thyroid- stimulating hormone (TSH). TSH stimulates the release of thyroxine. High levels of thyroxine in the blood inhibit secretion of TRH and TSH, which stops the release of additional thyroxine. Book’s explanation (a bit much): !!!!!

End Show 39-1 The Endocrine System Slide 29 of 44 Copyright Pearson Prentice Hall Negative feedback = the output of a pathway inhibits the inputs to the pathway. T3 & T4 are forms of thyroxine The end product shuts off the pathway that makes that product.

End Show 39-1 The Endocrine System Slide 30 of 44 Copyright Pearson Prentice Hall Control of the Endocrine System Controlling Metabolism Don’t write all of this but DO recognize the negative feedback loop.

End Show Slide 31 of 44 Copyright Pearson Prentice Hall 39-1 Which group of hormones act on target cells by binding directly to DNA in the nucleus? a.steroids b.nonsteroids c.proteins d.second messengers

End Show Slide 32 of 44 Copyright Pearson Prentice Hall 39-1 Metabolism is maintained by feedback loops involving the a.hypothalamus, gonads, and adrenal glands. b.hypothalamus, anterior pituitary, and thyroid gland. c.anterior pituitary, pancreas, and thyroid gland. d.thyroid gland, parathyroid gland, and pancreas.

End Show 39-1 The Endocrine System Slide 33 of 44 Copyright Pearson Prentice Hall What is the function of the pancreas? A digestive gland whose secretions help break down food. Also an endocrine gland which makes INSULIN & GLUCAGON These regulate levels of blood sugar, glucose!

End Show 39-1 The Endocrine System Slide 34 of 44 Copyright Pearson Prentice Hall What does the hormone INSULIN do? Insulin: stimulates cells in muscle & liver to REMOVE glucose from bloodstream First, remember that foods you eat are broken down and converted to glucose (sugar) Glucose is then used right away to make ATP OR liver converts and stores it (short-term) as glycogen OR gets converted & stored (long-term) as fat Glucose is then used right away to make ATP OR liver converts and stores it (short-term) as glycogen OR gets converted & stored (long-term) as fat

End Show 39-1 The Endocrine System Slide 35 of 44 Copyright Pearson Prentice Hall What does the opposite hormone, GLUCAGON do? Glucagon: stimulates cells in liver to change glycogen back into glucose and return it to bloodstream when you need it. Now the glucose is available as fuel to create ATP. Remember that glycogen: a SHORT term storage form of glucose

End Show 39-1 The Endocrine System Slide 36 of 44 Copyright Pearson Prentice Hall What is diabetes? Type I: an autoimmune disease in which person does not produce insulin. Type II: a lifestyle disease resulting from obesity. The body makes insulin but the cells are resistant to it. (also gestational diabetes = only during pregnancy) Show Mayo Clinic video clip.

End Show Slide 37 of 44 Copyright Pearson Prentice Hall 39-2 Diabetes mellitus is a disease that results when the pancreas fails to produce or properly use a.glucose. b.insulin. c.glucagon. d.carbohydrate.

End Show Slide 38 of 44 Copyright Pearson Prentice Hall 39-2 Metabolism is regulated by a.thyroxine. b.parathyroid hormone. c.epinephrine. d.estrogen.

End Show Slide 39 of 44 Copyright Pearson Prentice Hall 39-2 The gonads are the body's a.target cells. b.exocrine glands. c.reproductive glands. d.reproductive cells.

End Show Slide 40 of 44 Copyright Pearson Prentice Hall 39-2 Adrenaline (AKA epinephrine) is a hormone produced by the adrenal medulla and is responsible for a.the “fight or flight” response to stress. b.controlling the level of insulin in the blood. c.maintaining proper levels of sodium and potassium in the blood. d.regulating the water content of the body.