1. 1 PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Eleventh Edition Shier  Butler  Lewis Chapter 13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 2 Chapter 13 Endocrine System Endocrine glands are ductless Exocrine glands have ducts

3. 3 Endocrine Glands Endocrine glands release hormones hormones travel through blood to target cells Paracrine secretions act locally affect only neighboring cells Autocrine secretions affect only the secreting cell

4. 4 Comparison of Nervous System and Endocrine System Neurons release neurotransmitters into a synapse, affecting postsynaptic cells Glands release hormones into the bloodstream Only target cells of hormone responds

5. 5 Comparison of Nervous System and Endocrine System

6. 6 Major Endocrine Glands

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8. 8 Chemistry of Hormones Steroid or Steroid-Like Hormones sex hormones adrenal cortex hormones Nonsteroid Hormones amines proteins peptides glycoproteins most hormones

9. 9 Types of Hormones

10. 10 Structural Formulas of Hormones

11. 11 Actions of Steroid Hormones hormone crosses membranes hormone combines with receptor in nucleus synthesis of mRNA activated mRNA enters cytoplasm to direct synthesis of protein

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13. 13 Actions of Nonsteroid Hormones adenylate cyclase activated hormone binds to receptor on cell membrane ATP converted to cAMP cAMP promotes a series of reactions leading to cellular changes

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15. 15 Actions of Nonsteroid Hormones

16. 16 Prostaglandins paracrine substances act locally very potent in small amounts regulate cellular responses to hormones can activate or inhibit adenylate cyclase controls cAMP production alters cell’s response to hormones wide variety of functions

17. 17 Control of Hormonal Secretions primarily controlled by negative feedback mechanism

18. 18 Negative Feedback

19. 19 Major Endocrine Glands

20. 20 Pituitary Gland Two distinct portions anterior pituitary (adenohypophysis) posterior pituitary (neurohypophysis)

21. 21 Pituitary Gland Control Hypothalamic releasing hormones stimulate cells of anterior pituitary to release hormones Nerve impulses from hypothalamus stimulate nerve endings in the posterior pituitary gland to release hormones

22. 22 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Peripheral endocrine gland Anterior pituitary Hypothalamus Releasing hormone (Hormone 1) Anterior pituitary hormone (Hormone 2) Target cells (Hormone 3) Stimulation Inhibition + + + –– –

23. 23 Hypothalamic Hormones

24. 24 Hormones of the Pituitary Gland

25. 25 Thyroid Gland

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27. 27 Thyroid Gland Hormones

28. 28 Disorders of the Thyroid Gland

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30. 30 Disorders of the Thyroid Gland Cretinism Infantile hypothyroidism Graves Disease Hyperthyroidism

31. 31 Parathyroid Glands

32. 32 Parathyroid Hormone

33. 33 Parathyroid Hormone Mechanism by which PTH promotes calcium absorption in the intestine

34. 34 Calcium Balance

35. 35 Disorders of the Parathyroid Glands

36. 36 Adrenal Glands

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38. 38 Hormones of the Adrenal Medulla

39. 39 Hormones of the Adrenal Cortex

40. 40 Aldosterone – zona glomerulosa (mineralocorticoid) Cortisol – zona fasciculata (glucocorticoid) Sex hormones – zona reticularis (adrenal androgens) Hormones of the Adrenal Cortex

41. 41 Hormones of the Adrenal Cortex

42. 42 Hormones of the Adrenal Cortex

43. 43 Pancreas

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45. 45 Cell Types in the Pancreatic Islets Alpha cells (20%) produce glucagon Beta cells (70%) produce insulin Delta cells (5%) produce somatostatin F cells produce pancreatic polypeptide

46. 46 Hormones of the Pancreatic Islets

47. 47 Insulin and Glucagon Insulin and glucagon function together to stabilize blood glucose concentrations

48. 48 Other Endocrine Glands Pineal Gland secretes melatonin regulates circadian rhythms Thymus Gland secretes thymosins promotes development of certain lymphocytes important in role of immunity

49. 49 Other Endocrine Glands Reproductive ovaries produce estrogens and progesterone testes produce testosterone placenta produces estrogens, progesterone, and gonadotropins

50. 50 Hormonal Control of Male Reproductive Functions hypothalamus controls maturation of sperm cells and development of male secondary sex characteristics negative feedback among the hypothalamus, the anterior lobe of the pituitary gland, and the testes controls the concentration of testosterone

51. 51 Actions of Testosterone increased growth of body hair sometimes decreased growth of scalp hair enlargement of larynx and thickening of vocal cords thickening of skin increased muscular growth thickening and strengthening of the bones

52. 52 Hormonal Control of Female Reproductive Functions estrogens inhibit LH and FSH during most of the reproductive cycle

53. 53 Effects of Estrogens development of breasts and ductile system of the mammary glands increased adipose tissue in breasts, thighs, and buttocks increases vascularization of skin

54. 54 Female Reproductive Cycle

55. 55 Female Reproductive Cycle

56. 56 Hormonal Control of Female Secondary Sex Characteristics

57. 57 Menopause usually occurs in late 40s or early 50s reproductive cycles stop ovaries no longer produce as much estrogens and progesterone some female secondary sex characteristics may disappear may produce hot flashes and fatigue hormone therapy may prevent effects on bone tissue

58. 58 Mammary Glands located in the subcutaneous tissue of the anterior thorax within the breasts composed of lobes estrogens stimulate breast development in females

59. 59 Pineal Gland Small gland attached to 3rd ventricle of brain Consists of pinealocytes & neuroglia Melatonin responsible for setting of biological clock Jet lag & SAD treatment is bright light

60. 60 Effect of Light on Pineal Gland Melatonin secretion producing sleepiness occurs during darkness due to lack of stimulation from sympathetic ganglion

61. 61 Stress Types of Stress physical stress psychological stress

62. 62 Responses to Stress

63. 63 Life-Span Changes endocrine glands decrease in size muscular strength decreases as GH levels decrease ADH levels increase due to slower break down in liver and kidneys calcitonin levels decrease; increase risk of osteoporosis PTH level changes contribute to risk of osteoporosis insulin resistance may develop changes in melatonin secretion affect the body clock thymosin production declines increasing risk of infections

64. 64 Clinical Application Growth Hormone Ups and Downs Gigantism - hypersecretion of GH in children Acromegaly – hypersecretion of GH in adults Dwarfism – hyposecretion of GH in children Figure shows oversecretion of GH in adulthood as changes occur in the same person at ages (a) nine, (b) sixteen, (c) thirty-three, and (4) fifty-two

65. 65 Adrenal Cortex - Review Mineralocorticoids –Mineralocorticoids (e.g., aldosterone) increase sodium and water reabsorption and decrease potassium reabsorption, helping to regulate sodium and potassium levels in the body. –Secretion is controlled by the renin-angiotensin pathway (Figure 18.16) and the blood level of potassium. Glucocorticoids –Glucocorticoids (e.g., cortisol) promote breakdown of proteins, formation of glucose, lipolysis, resistance to stress, anti-inflammatory effects, and depression of the immune response. –Secretion is controlled by CRH (corticotropin releasing hormone) and ACTH (adrenocorticotropic hormone) from the anterior pituitary (Figure 18.17). Androgens –Androgens secreted by the adrenal cortex usually have minimal effects.

66. 66 Adrenal Medulla - Review The adrenal medulla consists of hormone-producing cells, called chromaffin cells, which surround large blood-filled sinuses. Medullary secretions are epinephrine and norepinephrine (NE), which produce effects similar to sympathetic responses. They are released under stress by direct innervation from the autonomic nervous system. Like the glucocorticoids of the adrenal cortex, these hormones help the body resist stress. However, unlike the cortical hormones, the medullary hormones are not essential for life. Table 18.8 summarizes the hormones produced by the adrenal glands, the principal actions, and control of secretion.

67. 67 Review: Cell Types in the Pancreatic Islets Alpha cells secrete the hormone glucagon which increases blood glucose levels. Beta cells secrete the hormone insulin which decreases blood glucose levels. Delta cells secrete growth hormone inhibiting hormone or somatostatin, which acts as a paracrine to inhibit the secretion of insulin and glucagon. F-cells secrete pancreatic polypeptide, which regulates release of pancreatic digestive enzymes.

68. 68 OVARIES AND TESTES - Review Ovaries are located in the pelvic cavity and produce sex hormones (estrogens and progesterone) related to development and maintenance of female sexual characteristics, reproductive cycle, pregnancy, lactation, and normal reproductive functions. The ovaries also produce inhibin and relaxin. Testes lie inside the scrotum and produce sex hormones (primarily testosterone) related to the development and maintenance of male sexual characteristics and normal reproductive functions. The testes also produce inhibin.

69. 69 PINEAL GLAND - Review The pineal gland (epiphysis cerebri) is attached to the roof of the third ventricle, inside the brain (Figure 18.1). Histologically, it consists of secretory parenchymal cells called pinealocytes, neuroglia cells, and scattered postganglionic sympathetic fibers. The pineal secrets melatonin in a diurnal rhythm linked to the dark-light cycle. Seasonal affective disorder (SAD), a type of depression that arises during the winter months when day length is short, is thought to be due, in part, to over-production of melatonin. Bright light therapy, repeated doses of several hours exposure to artificial light as bright as sunlight, may provide relief for this disorder and for jet lag.

70. 70 THYMUS GLAND The thymus gland secretes several hormones related to immunity. Thymosin, thymic humoral-factor, thymic factor, and thymopoietin promote the proliferation and maturation of T cells, a type of white blood cell involved in immunity.