Copyright © 2005, Elsevier, Inc. All rights reserved. Slide 0 0 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Chapter 10 The Endocrine System

1 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Distinguish between endocrine and exocrine glands and define the terms hormone and prostaglandins Identify and locate the primary endocrine glands and list the major hormones produced by each gland Describe the mechanisms of steroid and nonsteroid hormone action Learning Objectives

2 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Explain how negative and positive feedback mechanisms regulate the secretion of endocrine hormones Identify the principal functions of each major endocrine hormone and describe the conditions that may result from hyposecretion or hypersecretion Define diabetes insipidus, diabetes mellitus, gigantism, goiter, cretinism, and glycosuria Learning Objectives (cont’d)

Copyright © 2005, Elsevier, Inc. All rights reserved. Slide 3 3 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. What does the endocrine system do?

4 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Performs the same general functions as the nervous system  Communication  Control Provides slower, longer-lasting control by hormones secreted into and circulated by the blood The Endocrine System

5 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Question What are the two major classes of hormones?

6 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Mechanism of Nonsteroid Hormone Action

7 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Mechanism of Steroid Hormone Action

8 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Question What are the two major feedback loops used to maintain homeostasis in the body?

9 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Regulation of Hormone Secretion Hormone secretion is controlled by homeostatic feedback  Negative feedback: Mechanisms that reverse the direction of a change in a physiologic system  Positive feedback: (Uncommon) mechanisms that amplify physiologic changes

10 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Negative Feedback: Insulin

Copyright © 2005, Elsevier, Inc. All rights reserved. Slide Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. The Glands and Hormones

12 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Prostaglandins (or tissue hormones) are powerful substances found in a wide variety of body tissues A prostaglandin is often produced in a tissue and diffuses only a short distance to act on cells in that tissue Prostaglandins

13 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Prostaglandins (cont’d.) Several classes of prostaglandins include prostaglandin A, prostaglandin E, and prostaglandin F Prostaglandins influence many body functions, including respiration, blood pressure, gastrointestinal secretions, and reproduction

14 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pituitary Gland Anterior pituitary gland (adenohypophysis)  Major hormones  Thyroid-stimulating hormone (TSH)  Adrenocorticotropic hormone (ACTH)  Follicle-stimulating hormone (FSH)  Luteinizing hormone (LH)  Growth hormone (GH)  Prolactin hormone (PH)

15 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pituitary Gland (cont’d.)  Functions of major hormones  TSH o Stimulates growth of the thyroid gland o Stimulates it to secrete thyroid hormone  ACTH o Stimulates growth of the adrenal cortex o Stimulates thyroid to secrete glucocorticoids and mineralocorticoids

16 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved.  FSH o Initiates growth of ovarian follicles each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation o Stimulates estrogen secretion by developing follicles o Stimulates sperm production in the male Pituitary Gland (cont’d.)

17 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pituitary Gland (cont’d.)  LH o Acts with FSH to stimulate estrogen secretion and follicle growth to maturity o Causes ovulation o Causes luteinization of the ruptured follicle and stimulates progesterone secretion by corpus luteum o Causes interstitial cells in the testes to secrete testosterone in the male

18 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pituitary Gland (cont’d.)  GH o Stimulates growth by accelerating protein anabolism o Accelerates fat catabolism and slows glucose catabolism o By slowing glucose catabolism, tends to increase blood glucose to higher than normal level (hyperglycemia)

19 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved.  Prolactin or lactogenic hormone o Stimulates breast development during pregnancy and secretion of milk after the delivery of the baby Pituitary Gland (cont’d.)

20 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Posterior Pituitary Gland Hormones Antidiuretic hormone (ADH)  Accelerates water absorption from urine in the kidney tubules into the blood, thereby decreasing urine secretion Oxytocin  Stimulates the pregnant uterus to contract  May initiate labor  Causes glandular cells of the breast to release milk into ducts

21 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Hypothalamus Actual production of ADH and oxytocin occurs in the hypothalamus After production in the hypothalamus, hormones pass along axons into the pituitary gland The secretion and release of posterior pituitary hormones are controlled by nervous stimulation

22 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Conditions of pituitary and hypothalamus gland Hyperfunction results in –Giantism and acromegaly Hypofunction of pituitary results in dwarfism.

23 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Thyroid and Parathyroid Glands

24 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Thyroid Gland Hormones Thyroxine (T 4 )  Most abundant  To be produced in adequate amounts, diet must contain sufficient iodine Triiodothyronine (T 3 )  More potent  Considered by physiologists to be the principal thyroid hormone

25 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Calcitonin  Decreases the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood Thyroid Gland Hormones (cont’d)

26 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Parathyroid Gland Parathyroid hormone (PTH)  Increases blood calcium concentration by increasing the breakdown of bone with the release of calcium into the blood  Has opposite effect of calcitonin, because PTH acts to increase calcium

27 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Adrenal Glands Adrenal cortex  Three cell layers (zones) secrete hormones  Outer layer secretes mineralocorticoids  Middle layer secretes glucocorticoids  Inner layer secretes sex hormones, small amounts of male hormones (androgens) secreted by adrenal cortex of both sexes

28 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Mineralocorticoids Increase blood sodium Decrease body potassium concentrations by accelerating kidney tubule reabsorption of sodium and excretion of potassium

29 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Glucocorticoids Maintain normal blood glucose concentration by increasing gluconeogenesis, the formation of “new” glucose from amino acids produced by the breakdown of proteins, mainly those in muscle tissue cells

30 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Play an essential part in maintaining normal blood pressure Make it possible for epinephrine and norepinephrine to maintain a normal degree of vasoconstriction, a condition necessary for maintaining normal blood pressure Act with epinephrine and norepinephrine to produce an antiinflammatory effect to bring about normal recovery from inflammation of various kinds Produce antiimmunity, antiallergy effects Glucocorticoids (cont’d.)

31 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Results from hypersecretion of glucocorticoid hormone by a tumor of the middle zone of the adrenal cortex. Cushing Syndrome: Before and After Treatment

32 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Adrenal Glands Adrenal medulla  Hormones  Epinephrine (adrenaline)  Norepinephrine  Help the body resist stress by intensifying and prolonging the effects of sympathetic stimulation  An increased epinephrine secretion is the first endocrine response to stress

33 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pancreatic Islets Hormones  Glucagon is secreted by alpha cells  It increases the blood glucose level by accelerating liver glycogenolysis (conversion of glycogen to glucose)

34 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Insulin is secreted by beta cells.  It decreases the blood glucose by accelerating the movement of glucose out of the blood into cells, which increases glucose metabolism by cells. Pancreatic Islets (cont’d)

35 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Stress Responses Induced by High Concentrations of Glucocorticoids in Blood Stress Responses Induced by High Concentrations of Glucocorticoids in Blood

36 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Diabetes Mellitus

37 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Female Sex Glands The ovaries contain two structures that secrete hormones  The ovarian follicles  Little pockets in which egg cells, or ova, develop  Secrete estrogen, the “feminizing hormone”  The corpus luteum

38 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Effects of estrogen  Development and maturation of breasts and external genitals  Development of adult female body contours  Initiation of menstrual cycle Female Sex Glands (cont’d)

39 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Male Sex Glands The interstitial cells of the testes secrete the male hormone testosterone Effects of testosterone  Maturation of external genitals  Beard growth  Voice changes at puberty  Development of musculature and body contours typical of the male

40 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Thymus Hormone: Thymosin  This hormone plays an important role in the development and function of the body’s immune system

41 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Placenta Hormones  Chorionic gonadotropins: tropic hormones secreted by cells of the chorion, the outermost membrane that surrounds the baby during development in the uterus  Estrogens  Progesterone

42 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pineal Gland The pineal gland is a small gland near the roof of the third ventricle of the brain  Glandular tissue predominates in children and young adults  Tissue becomes fibrous and calcified with age  Called third eye because its influence on secretory activity is related to the amount of light entering the eyes

43 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Pineal Gland  Secretes melatonin, which  Inhibits ovarian activity  Regulates the body’s internal clock Pineal Gland (cont’d)

44 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Basic Anatomy - brain

45 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Other Endocrine Structures Other organs (stomach, intestines, and kidneys) produce endocrine hormones  Atrial natriuretic hormone (ANH)  Secreted by atrial wall of the heart  Stimulates sodium loss from the kidneys

46 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Leptin  Newly discovered hormone  Secreted by fat-storing cells  Controls how full or hungry we feel Other Endocrine Structures (cont’d)

Copyright © 2005, Elsevier, Inc. All rights reserved. Slide Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Let’s Review! Chapter 10

48 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 48 Which of these is a local regulator? A.Hormone B.Prostaglandin

49 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 49 Cortisol is produced by the A.Pituitary B.Thyroid C.Parathyroid D.Adrenal cortex E.Adrenal medulla

50 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 50 A primary role of melatonin is in A.Regulating reproductive functions B.Regulating the body’s internal clock C.Stimulating development of white blood cells D.Influencing water balance in the body E.Triggering the release of pituitary hormones

51 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 51 Which of these is a steroid hormone? A.Testosterone B.Melatonin C.Insulin D.Oxytocin E.Parathyroid hormone

52 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 52 The second messenger system is a form of A.Hormone manufacturing B.Signal transduction C.Local regulation D.Reusing or recycling old hormones E.Cheating

53 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Slide 53 Diabetes mellitus results from reduced effects of the hormone A.Glucagon B.Adrenalin C.Epinephrine D.Insulin E.Hydrocortisone

54 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Question What’s the difference between an endocrine and exocrine gland?

55 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Answer Endocrine glands are ductless glands, and they secrete hormones into intercellular spaces. Exocrine glands secrete into ducts that empty onto a surface or into a cavity.

56 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Question What is an example of a negative feedback loop for the regulation of hormone secretion?

57 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Answer There are many!! One example: – blood glucose triggers secretion of insulin. Since insulin promotes glucose uptake by cells, the blood glucose level is restored to its lower, normal level.

58 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Question Where is the pituitary gland located?

59 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Answer The pituitary gland lies buried deep in the cranial cavity in the small depression of the sphenoid bone. The pituitary stalk attaches the gland to the hypothalamus.

60 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Questions What are the zones or areas of the adrenal cortex? What are the hormones produced by the zones or areas of the adrenal cortex?

61 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Answers The outer zone secretes hormones called mineralocorticoids; the main mineralocorticoid is the hormone aldosterone. The middle zone secretes glucocorticoids; the main hormone is hydrocortisone. The inner zone secretes small amounts of sex hormones that resemble testosterone.

62 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Critical Thinking Question We have already studied the nervous system and discussed its many important functions. What functions do the endocrine system and nervous system have in common?

63 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. Answer The endocrine system and nervous system have the same general functions: communication and control. The nervous system provides rapid, brief control by fast-traveling nerve impulses, whereas the endocrine system provides slower but longer-lasting control.

64 Copyright (c) 2008, 2005 by Mosby, Inc., an affiliate of Elsevier Inc. All rights reserved. ???????????????? What questions do you have for me? Don’t forget that your final project is due to the dropbox no later than midnight ET on Tuesday night!!