1. 13 Unit 1 Chapter 13

2. 13 Unit 1 to interstitial fluid  circulation exocrine- secreted to ducts  lumen or outside the body Endocrine glands: Pituitary, thyroid, parathyroid, adrenal & pineal Hormone secretion + other functions: Hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, skin, heart, adipose tissue & placenta

3. Figure 13.1

4. 13 Unit 1 General chemical signal in circulation Slower than nerve responses Target cells must have a specific receptor Response determined by responding cell, i.e. different cells may respond differently to the same hormone Cell may respond to more than one hormone, i.e. has more than one type receptor

5. 13 Unit 1 Soluble in lipids = Hydrophobic steroids, e.g. testosterone, estrogens, etc. thyroid hormones, e.g. T 3, T 4 Nitric oxide (NO) Water soluble= Hydrophillic Amino acid derivatives, e.g. epinephrine, norepinephrine Peptides, e.g. antidiuretic Hormone (ADH), oxytocin Proteins, e.g. insulin & growth hormone General Action depends on chemistry

6. 13 Unit 1 Hormone detaches from carrier in blood stream Diffusion through interstitial fluid & cell membrane into cell Binds to & activates receptor Receptor-hormone complex alters gene expression If new mRNA  protein synthesis New proteins alter cell activity

7. Figure 13.2

8. 13 Unit 1 Diffuses from blood and binds to receptor in plasma membrane Starts reaction inside cell forming second messenger Cyclic AMP is a common one Second messenger causes activation of several proteins (enzymes) Activated proteins produce physiological responses Second messenger is inactivated

9. Figure 13.3

10. 13 Unit 1 Release occurs in short bursts Regulated by: Signals from nervous system, e.g. adrenal medulla release of epinephrine Chemical changes in blood, e.g Blood Ca 2+ affects parathyroid hormone Other hormones, e.g. ACTH from pituitary stimulates cortisol release from adrenal cortex

11. 13 Unit 1 Major link between nervous & endocrine systems Hypothalamic Cells synthesize at least 9 hormones Pituitary synthesizes 7 Regulate growth, development, metabolism & homeostasis

12. 13 Unit 1 Two lobes; anterior & posterior Hypophyseal portal veins Connect capillaries in hypothalamus to capillaries in anterior pituitary

13. 13 Unit 1 Axons of hypothalamic neurons (neurosecretory cells) end near capillaries of hypothalamus Secrete Releasing hormones or Inhibiting hormones  portal veins  Regulate release of anterior pituitary hormones

14. Figure 13.4

15. 13 Unit 1 Promotes synthesis of IGFs = somatomedins in liver, muscle, cartilage & bone Released in bursts (~2 hour intervals) Hypothalamus  Growth Hormone Releasing Hormone (GHRH) & Growth Hormone Inhibiting Hormone (GHIH ) Regulated by blood glucose levels

16. 13 Unit 1 Stimulates the formation & secretion of Thyroid hormones from thyroid gland Hypothalamus  Thyrotropin Releasing Hormone (TRH)- no TIH Regulated by circulating thyroid hormone levels

17. 13 Unit 1 In females: FSH starts follicle development LH stimulates formation of corpus luteum & secretion of progesterone In males: FSH stimulates sperm production in testes LH stimulates release of testosterone Gonadotrophin releasing Hormone (GnRH) from hypothalamus is suppressed by high levels of estrogen in females and testosterone in males

18. 13 Unit 1 Initiates & maintains milk production by mammary glands Ejection of milk depends on oxytocin Prolactin inhibiting hormone (PIH) suppresses prolactin release High levels of Estrogens  PRH  prolactin release Unknown function in males Hypersecretion  impotence

19. 13 Unit 1 Controls production & secretion of glucocorticoids from adrenal cortex Corticotrophin Releasing Hormone (CRH) from hypothalamus stimulates secretion of ACTH Stress related stimuli can also stimulate ACTH release Glucocorticoids inhibit CRH & ACTH release

20. 13 Unit 1 Small circulating amounts Excess causes skin darkening

21. 13 Unit 1 axon terminals from hypothalamus- Release hormones Oxytocin- enhance smooth muscle contraction during birth & milk ejection may play role in emotional bonding Antidiuretic Hormone (ADH) = vasopressin Causes kidney to retain more water Vasoconstriction  increase in blood pressure high blood osmotic pressure  increase secretion

22. Figure 13.5

23. Figure 13.6

24. 13 Unit 1 Below larynx- two lobes follicular cells surround follicles  thyroxin (T 4 ) & triiodothyronine (T 3 ) Stored in follicle Parafollicular cells (C-cells)  calcitonin

25. Figure 13.7a

26. Figure 13.7b

27. 13 Unit 1 T 4 & T 3 increase basal metabolic rate, protein synthesis & growth Blood level is controlled via feedback through hypothalamus Increased body ATP demand can also raise blood levels Calcitonin inhibits osteoclasts  decrease in blood Ca 2+ Feedback control on blood levels

28. Figure 13.8

29. 13 Unit 1 Small round masses in posterior of thyroid gland Chief cells release parathyroid hormone (PTH) Regulator of Ca 2+, Mg 2+ & HPO 4 2- Increases number & activity of osteoblasts Slows loss of Ca 2+ & Mg 2+ in urine Promotes production of calcitriol  increases rate of Ca 2+, Mg 2+ & HPO 4 2- absorption in GI tract

30. Figure 13.9

31. Figure 13.10

32. 13 Unit 1 Fattened organ in curve of duodenum Mostly an exocrine organ for digestion Endocrine cells in pancreatic islets Several cell types: alpha cells  glucagon beta cells  insulin

33. Figure 13.11a

34. Figure 13.11b

35. Figure 13.11c

36. 13 Unit 1 Low blood glucose stimulates glucagon release Glucagon stimulates liver glucose release  increased blood glucose High glucose levels stimulate insulin release Insulin increase glucose transport into skeletal muscle and adipose cells  decreased blood glucose Insulin promotes Amino Acid uptake, protein synthesis & lipid storage ANS also modulates hormone release

37. Figure 13.12

38. 13 Unit 1 Near kidneys Two separate gland structures- Adrenal cortex and adrenal medulla 3 zones in Cortex-3 steroid hormones Outer zone  mineralocorticoids Middle zone  glucocorticoids Inner Zone  androgens

39. Figure 13.13a

40. Figure 13.13b

41. 13 Unit 1 Aldosterone is the major form Stimulates Na + reabsorption from urine to blood Stimulates excretion of K + into urine Part of renin-angiotensin-aldosterone pathway Decreased BP  release of renin from kidney Renin causes angiotensinogen  angiotensin I In lungs Angiotensin converting enzyme (ACE) causes Angiotensin I  angiotensin II Angiotensin II causes Aldosterone release

42. Figure 13.14

43. 13 Unit 1 Increase rate of protein breakdown Stimulate liver formation of glucose Breakdown of triglycerides in adipose Anti-inflammatory effects- Inhibit white blood cells Depresses immune system Regulated by negative feedback through hypothalamus

44. 13 Unit 1 Small amount secreted from adrenal cortex Contribute to libido in females Converted to estrogens by other body tissues Stimulate axillary hair growth in both boys & girls Contribute to adolescent growth spurt

45. 13 Unit 1 Consists of sympathetic post ganglionic cells stimulated by preganglionic sympathetic neurons Releases Epinephrine and norepinephrine gives systemic sympathetic effects occurs during strong physiological stress

46. 13 Unit 1 Produce gametes Release sex steroids (testosterone or estrogen & progesterone) Also hormone inhibin Inhibits FSH release hormones from pituitary (FSH & LH) Ovaries also produce a hormone relaxin during pregnancy details later in course

47. 13 Unit 1 Small gland attached to roof of third ventricle of brain Produces melatonin Sets bodies biological clock More released in darkness

48. 13 Unit 1 Prostaglandins (PG) & leukotrienes (LT) Derived from fatty acids Act locally in most tissues & released from most body cells LTs stimulate white blood cells & mediate inflammation PGs affect many visceral functions & also modulate inflammation, promote fever & intensify pain

49. 13 Unit 1 Part of homeostatic responses When successful leads to extra physiological capacity and long term adaptation Initial “fight-or-flight” response Nerve mediated response-sympathetic

50. 13 Unit 1 Slower & longer Than initial response Hypothalamus  Increased CRH, GHRH, TRH CRH  ACTH  Cortisol  mobilize metabolites (amino acids, glucose & fat) GHRH  hGH  mobilize fats & glucose for energy and promote tissue growth & repair TRH  TSH  thyroid hormones  increased Metabolic capacity

51. 13 Unit 1 Some decrease in function with aging Loss of negative feedback sensitivity, e.g. decline in circulating thyroid hormones PTH levels rise  loss of bone mass Less glucocorticoid production Slower release of insulin Thymus declines after puberty Ovary response to gonadotrophins stops Slow decline in testosterone production