1. ENDOCRINE SYSTEM

2. Homeostasis & Controls Successful compensation –Homeostasis Failure to compensate –Pathophysiology Illness Figure 1-5: Homeostasis

3. ENDOCRINE SYSTEM Uses chemical signals for cell to cell Coordinates the Response to an endocrine signal occurs within

4. Chemical Regulating Systems: Overview Pheromones: organism to communication Hormones: cell to cell communication molecules –Made in –Transported by –Distant target tissue – physiological response

5. Paracrines and Autocrines Local Signal chemicals diffuse to Example: –Autocrine–receptor on same cell –Paracrine–neighboring cells Figure 6-1c: Direct and local cell-to-cell communication

6. Signal Made in cells Transported via Receptors on cells Long Distance Communication: Hormones Figure 6-2a: Long distance cell-to-cell communication

7. Figure 6-2b, c: Long distance cell-to-cell communication

8. Signal Pathways Signal molecule Receptor signal Target Response Figure 6-3: Signal pathways

9. Membrane associated e –External reactions –Internal reactions Receptors bind specific – Example: Hormones –Cell molecules Figure 5-6: Cell membrane receptor

10. HORMONE CLASSIFICATION Protein and A S

11. PEPTIDE HORMONES Consist of specific Synthesized as large Stored in membrane- compartments H

12. Surface binds T E Open Second messenger systems S Protein and Polypeptide Hormone Receptors Figure 7-5: Membrane receptors for peptide hormones

13. AMINE HORMONES Derived from the amino acid Includes thyroid hormones and catecholamines Stored until

14. Receptors –Surface –I–I Small size, group Examples –T–T –E–E Amine Hormones

15. STEROID HORMONES Precursor: C L Immediately released from the cell following synthesis

16. Cytoplasmic or receptors (mostly) Activate for protein synthesis Slower acting, longer Examples: cortisol, estrogen & t Steroid Hormones

17. Steroid Hormones: Action Figure 7-7: Steroid hormone action

18. Summary of the Endocrine System Figure 7-2-1: ANATOMY SUMMARY: Hormones

19. Figure 6-26: Negative and positive feedback

20. HYPOTHALAMUS Integrates functions that maintain chemical and temperature Functions with the system Controls the release of hormones from the anterior and posterior pituitary

21. Figure 11-3: Autonomic control centers in the brain

22. HYPOTHALAMUS Synthesizes & releases hypophysiotropic hormones: –T -releasing hormone (TRH) –C -releasing hormone (CRH) –G -releasing hormone (GnRH) –G hormone-releasing hormone (GHRH) –Growth hormone- hormone (GHIH) –P -releasing factor (PRF) –Prolactin- hormone (PIH)

23. HYPOTHALAMUS Synthesizes hypophysiotropic hormones in bodies of neurons located in the hypothalamus Transports hormones down the and stored in the nerve endings Secretion of hormones is in

24. HYPOTHALAMUS: Secretion of Hypophysiotropic Hormones Is influenced by Can be influenced by the state of the individual Delivered to the pituitary via the hypothalamic-hypophyseal portal system Usually initiates a -hormone sequence

25. Negative Feedback Controls: Long & Short Loop Figure 7-14: Negative feedback loops in the hypothalamicanterior pituitary pathway

26. Feedback Controls: Long & Short Loop Reflexes Figure 7-15: Control pathway for cortisol secretion

27. Endocrine Control: Three Levels of Figure 7-13: Hormones of the hypothalamic-anterior pituitary pathway

28. ANTERIOR PITUITARY

29. ANTERIOR PITUITARY HORMONES Growth Hormone (GH, Somatotropin): primary hormone responsible for regulating body growth, and is important in Thyroid-stimulating Hormone (TSH): stimulates secretion of hormone & growth of thyroid gland Adrenocorticotropic Hormone (ACTH): stimulates secretion by the adrenal cortex & promotes growth of adrenal cortex

30. ANTERIOR PITUITARY Follicle-stimulating Hormone (FSH): Females: stimulates growth & development of follicles, promotes secretion of estrogen by ovaries. Males: required for production Luteinizing Hormone (LH): Females: responsible for o, formation of corpus luteum in the ovary, and regulation of ovarian secretion of female sex hormones. Males: stimulates cell in the testes to secrete Prolactin: Females: stimulates development and milk production. Males: involved in testicular function

31. ANTERIOR PITUITARY Synthesis of different anterior pituitary hormone is by different cell populations. Corticotropes - Lactortropes - Somatotropes - Thyrotropes - Gonadotropes -

32. Hypothalamic stimulation–from Pituitary stimulation–from hypothalamic Hs Endocrine gland stimulation–from pituitary Hs Endocrine Control: Three Levels of Integration

33. Pathologies: Over or Under Production Figure 7-19: Negative feedback by exogenous cortisol

34. Pathologies: Due to Receptors Figure 7-20: Primary and secondary hypersecretion of cortisol

35. POSTERIOR PITUITARY Comprised of the endings of axons from cell bodies in the hypothalamus (s and paraventricular) Axons pass from the hypothalamus to the posterior pituitary via the tract Posterior pituitary hormones are synthesized in the cell bodies of in the supraoptic and paraventricular nuclei

36. POSTERIOR PITUITARY Hormones synthesized in the hypothalamus are transported down the axons to the endings in the posterior pituitary Hormones are stored in vesicles in the posterior pituitary until release into the Principal Hormones: Vasopressin &

37. Figure 7-12: Synthesis, storage, and release of posterior pituitary hormones

38. POSTERIOR PITUITARY Oxytocin: Synthesized as the precursor hormone: Action primarily on the Increases contraction of smooth muscle of Vas Deferens

39. POSTERIOR PITUITARY Vasopressin Plasma osmolality is monitored by osmoreceptors in the hypothalamus Increases in plasma osmolality stimulates secretion of Small changes above normal plasma osmotic pressure ( 285 mosm/kg) stimulate release of

40. POSTERIOR PITUITARY Vasopressin secretion also stimulated by: 1.Large in blood volume 2.Decreases in

41. POSTERIOR PITUITARY Vasopression Action: Decreases excretion by kidneys (V2 receptors) Constricts (V1 receptors) Increases adrenocorticortropin Hormone (V receptors)

42. Summary of the Endocrine System Figure 7-2-3: ANATOMY SUMMARY: Hormones

43. Summary of the Endocrine System Figure 7-2-2: ANATOMY SUMMARY: Hormones

44. Endocrine Disorders Acromegaly – excessive – large hands, feet, body size respiratory and circulatory problems

45. Grave’s Disease – bulging eyeballs, nervousness, elevated pulse, wgt. loss from too much Bone Fractures – excessive Cushing’s - moon face, poor immune sys. – caused by ↑ Increased hair growth, masculinazation – caused by ↑ Diabetes mellitus – low insulin – symptoms = 1.Polyuria ↑sugar in kidneys (↑water in urine 2.Polydipsia ↑thrist 3.Polyphagia ↑hunger because sugar is not being used.