Ch%2047064 - CHAPTER 47 THE ENDOCRINE SYSTEM TIPS FOR...

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Unformatted text preview: CHAPTER 47 THE ENDOCRINE SYSTEM TIPS FOR MASTERING KEY CONCEPTS The central nervous system processes incoming information from the sensory system and sends out response commands. Some of these orders given by the central nervous system are carried out by hormones produced by endocrine glands. These activities help regulate body activities and unite a diverse collection ofcells, tissues. and organs into a smoothly functioning single organism that can maintain the homeostasis necessary for life. Not all hormones, however, are under the control of the nervous system, and the nervous system itself is influenced by hormones. 47.] Regulation is often accomplished by chemical messengers. - The body produces many types of chemical messengers, including neurotransmitters. hormones. and paracrine regulators. all of which help control and coordinate the functioning of organs and organ systems. 0 Endocrine glands produce hormones that are transported in the blood to reach their target organs and cells. - Hormones are chemically diverse and have wide- ranging, diverse impacts. - Paracrine regulators are also diverse, but their impact is on the organ that produces them. 0 There is close linkage and interaction between the nervous system and the endocrine system. 47.2 Lipophilic and polar hormones regulate their target cells by different means. - Lipophilic hormones (thyroxine and the steroid hormones) are nonpolar and lipid-soluble. They enter their target cells, bind to a protein receptor and directly influence specific genes in the nucleus of the target cell. 0 Hormones that are polar or very large cannot enter theirtarget cells and use a two-messenger system instead. They bind to the first messenger, a protein receptor on the plasma membrane, and cause a chemical chain reaction within the target cell that is initiated by the second messenger. 297 47.3 The hypothalamus controls the secretions of the pituitary gland. The posterior pituitary gland is anatomically connected to the anterior pituitary gland, but the two are not functionally connected. The hormones ADH and oxytocin are produced by the hypothalamus of the brain, travel down axons that connect the hypothalamus and posterior pituitary, and are stored in and then released from the posterior pituitary. The hypothalamus also produces releasing and inhibiting hormones that travel to the anterior pituitary gland via a portal system of blood vessels. The releasing and inhibiting hormones stimulate or inhibit the production ofa variety oftropic hormones by the anterior pituitary glands. These tropic hormones have a variety of target organs. including other endocrine glands. and a variety ofimpacts. 47.4 Endocrine glands secrete hormones that regulate many body functions. Hormones from the thyroid gland regulate metabolic rate and calcium levels in the blood. Hormones from the parathyroid glands also help regulate calcium levels. The adrenal medulla secretes hormones as part of the fight—or-flight response. The adrenal cortex hormones regulate glucose, sodium, and potassium levels in the blood. Cells within the pancreas produce hormones that regulate glucose levels in the blood. The ovaries and testes produce sex hormones that regulate sexual maturation and reproduction. The pineal gland produces melatonin, which is involved in regulating circadian and seasonal physiological rhythms. The thymus, heart, and kidneys also produce hormones. Molting and metamorphosis of insects are under hormonal control. Some environmental contaminants can disrupt normal functioning of the endocrine system. MAP OF UNDERSTANDING The following map shows the relationships of the chapter concepts to each other. HORMONE CHAIN OF COMMAND Hypothalarnus Releasing and Inhibiting Hormones Anterior Pituitary Tropic Hormones Target Organ (Hormone Produced or Some Other Response Carried Out) KEY TERMS 47.1 growth factors anterior pituitary hormone neurotrophins posterior pituitary endocrine gland prostaglandins antidiuretic hormone (ADI-l) target cells nonsteroidal anti-inammatory vasopressin neurohorrnone drugs (NSAIDs) oxytocin paracrinc 47.2 neuroendocrine reflexes sex steroids cyclic AMP {CAMP} insulin-like growth factors corticosteroids adenylyl cyclase 47.4 catecholamines protein kinase-A brain hormone lipophilic hormones 47.3 juvenile hormone cytokines pituitary gland LEARNING BY EXPERIENCE l. Hormones that have opposite effects are called antagonistic. Arrange the following six hormones into their proper antagonistic pairs and indicate what physiological parameter the pair regulates. Hormones: calcitonin, aldosterone. glucagon. parathyroid hormone. insulin. atrial natriuretic hormone. Pairs Regulates 298 Complete the following table about the endocrine system by filling in the blanks with the appropriate term. Hormone Where Produced Function Thyroxine a. _ _" Increase metabolic rate ACTH b. c. ___ d. e Stimulate uterine contractions. milk ejection Insulin l“. i__fi ~ g. j“ _k_% Diagram the hormonal chain ot‘cominand by using the following terms to fill in the blanks below. Each blank should contain the name ot‘the organ and the hormone it produces. Terms: anterior pituitary. hypothalamus. luteinizing hormone (LH)~ ovary. progesterone. gonadotropin-releasing hormone (Gan—l). Chain of Command: 299 EXERCISING YOUR KNOWLEDGE Briefly answer each of the following questions in the space provided. I. Compare and contrast neurotransmitters and hormones in terms of where they are produced and how they Function. 2. Compare and contrast paracrine regulators and pheromones in terms of‘ how they function. 3. Why can't water-soluble hormones enter cells? 4. In the two-messenger system of‘ hormone action, where are the two messengers located, and what are their basic functions? Why does epinephrine have such diverse effects on different tissues ofthe body? 300 6. What do the anterior and posterior pituitary III ' 10. in common? What is different about them? Many of the symptoms of a hangover are ca . ~- - 5 by dehydration. Why? ‘ Why is negative feedback, rather than positive feedback, used to control the hypothalamus and anterior pituitary? l Peeple with diabetes have high levels of glucose L in their blood. People with hypoglycemia have the opposite problem — low blood glucose levels. Besides fasting, what else might cause hypoglycemia, and why can it be a serious problem? f Why can some hormones be taken orally (e.g.. female sex hormones in contraceptive pills), but other hon-nones must be injected (e.g., insulin) to I be effective? Circle the letter of the one best answer in each of the following questions. 11. Insulin and ADH are examples of Hm” . w.” ,m “W .V. < . g 13. g E 14. 3‘ 15. gf. 16. a b c d e a. b. c. d steroid hormones. amine hormones. polypeptide hormones. glycoproteins. pheromones. 12. Norepinephrine is a neurotransmitter. hormone. both of these. neither of these. Which of the following statements about prostaglandins is true? a. Aspirin promotes the production of prostaglandins. b. Prostaglandins are produced only by endocrine glands. c. Prostaglandins travel in the circulatory system to reach their target cells. d. All of these are true. e. None of these are true. Cytokines a. regulate different cells of the immune system. b. promote growth and cell division in specific organs. c. help maintain proper mineral balance in the body. (1. help maintain proper water balance in the body. 6. regulate reproductive cycles. Which of the following types of hormones enter their target cells? 9999'.» polypeptide hormones steroid hormones glycoprotein hormones all of these none of these Lipophilic hormones a.‘ b. c. d. e are able to enter their target cells. are lipid soluble. attach to protein receptors and DNA. All of these are correct. None of these are correct. 301 17. 18. 19. 20. 21. 22. 23. In the two-messenger system of hormone activity, what is the first messenger? the endocrine gland the hormone DNA a receptor protein on the target cells plasma membrane 6. cyclic AMP 9—957? Which endocrine gland develops from an outgrowth of the epithelium lining the roof of the mouth? a. anterior pituitary b. posterior pituitary c. pineal gland d. hypothalamus e. thymus Releasing hormones are produced by a. various endocrine glands. b. the anterior pituitary. c. the posterior pituitary. d. the pineal gland. e. the hypothalamus. Releasing hormones directly affect a. various target organs. b. the anterior pituitary. c. the posterior pituitary. d. the pineal gland. e. the hypothalamus. Which of the following hormones has no knovm function in mammals? a. GnRH b. PRL c. MSH d. calcitonin e. oxytocin ADH and oxytocin are produced by the a. hypothalamus. b. posterior pituitary. c. anterior pituitary. d. adrenal cortex. e. adrenal medulla. If your ADH levels are really high, your urine will be a. very dilute. b. very concentrated. c. alcoholic. 24. 25. 26. 27. Robert Wadlow grew to a gigantic size because ofa tumor in his a. thyroid gland. b adrenal cortex. c. adrenal medulla. d. anterior pituitary. e. posterior pituitary The target organ{s) for luteinizing hormone is(are) the a. liver. b. kidneys. c. bones. d. pancreas e. gonads. A portal system connects the a. anterior and posterior pituitary glands. b. anterior pituitary and the hypothalamus. c. posterior pituitary and the hypothalamus. d. thyroid and parathyroid glands. e. adrenal cortex and the adrenal medulla. According to the text, which two hormones are most essential for your survival? estrogen and testosterone calcitonin and insulin parathyroid hormone and aldosterone somatotropin and cortisol ADI-l and thyroxine 999?? 302 28. 29. 30. Type I diabetes is caused by a deficiency. of 1' a. exercise. z- ‘ b. glucagon. :; :2. glucose. ‘- d glycogen. e insulin. In an insect that is about to undergo metamorphosis, what levels of juvenile - . V and ecdysone would you expect to find? ' low juvenile. low ecdysone high juvenile, high ecdysone high juvenile, low ecdysone low juvenile, high ecdysone You would not find any hormones in an insect. 9999'?“ Which of the following pairs is properly . matched? 1 a. insulin — produced by the beta oells of the _ islets of Langerhans in the pancreas ’ ‘ b. aldosterone — produced by the adrenal medulla c. parathyroid hormone — regulates Na‘” and --; levels in the blood ' ' d. calcitonin — stimulates oxidative respirari melatonin — produced by the thymus ‘ ' 5‘ ...
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This note was uploaded on 09/13/2008 for the course BIOL 1720 taught by Professor Jagadeeswaran during the Spring '08 term at North Texas.

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Ch%2047064 - CHAPTER 47 THE ENDOCRINE SYSTEM TIPS FOR...

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