Biology Chapter 39 The Endocrine System Slide 1 of 44 Copyright Pearson Prentice Hall End Show What is the function of the endocrine system? To release hormones, which send messages throughout the body via the blood stream. Slide 2 of 44 Copyright Pearson Prentice Hall End Show 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 Slide 3 of 44 Copyright Pearson Prentice Hall End Show 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. Slide 4 of 44 Copyright Pearson Prentice Hall End Show 39-1 Cells that have receptors for a particular hormone are called a. nerve cells. b. target cells. c. exocrine cells. d. endocrine cells. Slide 5 of 44 End Show 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. Slide 6 of 44 End Show Copyright Pearson Prentice Hall 39-1 The Endocrine System Glands DO NOT WRITE ANYTHING. JUST READ Hypothalamus The hypothalamus makes hormones that control the pituitary gland. In addition, the hypothalamus makes hormones that are stored in the pituitary gland. Slide 7 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands. Slide 8 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Parathyroid glands The parathyroid glands release parathyroid hormone, which regulates the level of calcium in the blood. Slide 9 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Thymus During childhood, the thymus releases thymosin, which stimulates T cell development and proper immune response. This is important. Write it down. Slide 10 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Adrenal glands The adrenal glands release adrenaline and norepinephrine, which help the body respond to stress. (Fight or flight response) Know this one. Slide 11 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics. Slide 12 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System 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. Slide 13 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Pancreas The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood. Slide 14 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Thyroid The thyroid produces thyroxine, which regulates metabolism throughout the body. Slide 15 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Glands Pineal gland The pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles. Slide 16 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System How are hormones classified? Some are STEROID hormones made from a lipid (fat) called cholesterol Steroid hormones can cross cell membranes easily. Slide 17 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System The Endocrine System Steroid Hormone Action Steroid hormone Receptor Nucleus Hormone-receptor complex: notice this directly affects gene expression. Altered cellular function DNA Protein synthesis mRNA Copyright Pearson Prentice Hall Slide 18 of 44 End Show 39-1 The Endocrine System A steroid hormone enters a cell directly across its membrane. The Endocrine System Steroid hormone It binds to a receptor to form a hormonereceptor complex. Receptor Hormone-receptor complex Slide 19 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System 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. DNA Nucleus mRNA Slide 20 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System The Endocrine System mRNA moves into the cytoplasm to direct protein synthesis. Altered cellular function Protein synthesis Slide 21 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System How are hormones classified? Hormone Action There are also nonsteroid hormones which include proteins, small peptides and modified amino acids. Nonsteroid hormones CANNOT pass through the cell membrane. Slide 22 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System The Endocrine System Nonsteroid hormone (first messenger) A nonsteroid hormone binds to receptors ON THE CELL MEMBRANE. This activates an enzyme on the inside of the membrane. Slide 23 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System 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 Slide 24 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System How does the endocrine system maintain homeostasis? The endocrine system is regulated by FEEDBACK mechanisms that function to maintain homeostasis. Slide 25 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System What is an example of feedback regulation Control of the Endocrine System 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. Slide 26 of 44 Copyright Pearson Prentice Hall End Show Problems: 1. How will the body know it should make more thyroxine? 2. How will it know when it has made enough thyroxine? Slide 27 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Control of the Endocrine System Book’s explanation (a bit much): If thyroxine is low, the hypothalamus secretes thyrotropin-releasing hormone (TRH), which stimulates the anterior pituitary to secrete thyroidstimulating 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. !!!!! Slide 28 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System Negative feedback = the output of a pathway inhibits the inputs to the pathway. The end product shuts off the pathway that makes that product. T3 & T4 are forms of thyroxine Slide 29 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System 1 Control of the Endocrine System 7 Controlling Metabolism 2 3 Don’t write all of this but DO recognize the negative feedback loop. 4 5 Slide 30 of 44 6 Copyright Pearson Prentice Hall End Show 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 Slide 31 of 44 End Show 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. Slide 32 of 44 End Show Copyright Pearson Prentice Hall 39-1 The Endocrine System 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! Slide 33 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System First, remember that foods you eat are broken down and converted to glucose (sugar) What does the hormone INSULIN do? Insulin: stimulates cells in muscle & liver to REMOVE glucose from bloodstream • 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 Copyright Pearson Prentice Hall Slide 34 of 44 End Show 39-1 The Endocrine System What does the opposite hormone, GLUCAGON do? Remember that glycogen: a SHORT term storage form of glucose 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. Slide 35 of 44 Copyright Pearson Prentice Hall End Show 39-1 The Endocrine System What is diabetes? Show Mayo Clinic video clip. 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) Copyright Pearson Prentice Hall Slide 36 of 44 End Show 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. Slide 37 of 44 End Show Copyright Pearson Prentice Hall 39-2 Metabolism is regulated by a. thyroxine. b. parathyroid hormone. c. epinephrine. d. estrogen. Slide 38 of 44 End Show Copyright Pearson Prentice Hall 39-2 The gonads are the body's a. target cells. b. exocrine glands. c. reproductive glands. d. reproductive cells. Slide 39 of 44 End Show 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. Slide 40 of 44 End Show Copyright Pearson Prentice Hall