1. The Endocrine System Michael Hall PhD University of California Los Angeles University of California Los Angeles

2. Modes of secretion and action of chemical messengers (hormones) Modes of secretion and action of chemical messengers (hormones) autocrineparacrineendocrinesynaptic target cell Chemical messenger receptors

3. Classes of Chemical Messengers 1.Amino acid derivatives (eg thyroxine, adrenaline) 2.Small peptides (eg vasopressin, thyroid releasing hormone) 3. Proteins (eg insulin, growth hormone) 4. Steroids (eg cortisol, testosterone, progesterone)

4. Positive and negative feedback control of hormone production Positive and negative feedback control of hormone production

5. Higher brain centers Hypothalamus Anterior Pituitary Adrenal cortex Adrenal medulla Epinephrine Anterior Pituitary Thyroid follicular cells Various tissues neurotransmitters TRH CRH TSH ACTH T3/T4 Cortisol Various tissues Sensory neuronal stimulation

6. Diffuse NeuroEndocrine System The DNES involves a number of isolated cells, or small groups of cells, that are situated throughout the body, but particularly in the digestive, respiratory and urinary systems. These cells, called APUD cells, secrete chemical messengers that generally act in a paracrine manner.

7. The Endocrine Glands Most organs have some endocrine function. The next lectures will deal with organs whose only functions are to secrete hormones: Pituitary Thyroid Parathyroid Adrenal Pancreas * *Pancreas has both endocrine and exocrine functions The Endocrine Glands Most organs have some endocrine function. The next lectures will deal with organs whose only functions are to secrete hormones: Pituitary Thyroid Parathyroid Adrenal Pancreas * *Pancreas has both endocrine and exocrine functions

8. Pituitary Gland

9. Pituitary hormones and their target organs

10. Development of the pituitary gland infundibulum (stalk) median eminence hypothalamus pars nervosa

12. pars tuberalis median eminence hypothalamus infundibulum (stalk) pars nervosa pars distalis pars intermedia Hypothalamus and Pituitary posterior anterior

13. Hormone production and release by the neurohypophysis ( pars nervosa) ( pars distalis) (oxytocin) (ADH)

14. Herring body Pituicytes (glial cells) Pituicytes (glial cells) Herring body in neurohypophysis

15. Herring Bodies along a Capillary Secretory granule Axon terminal Capillary Secretory granule Axon terminal Capillary

16. pars tuberalis median eminence hypothalamus infundibulum (stalk) pars nervosa pars distalis pars intermedia Hypothalamus and Pituitary posterior anterior

17. Development of the pituitary gland infundibulum (stalk) median eminence hypothalamus pars nervosa

18. Chromophobes Acidophils Chromophils and Chromophobes in the Adenohypophysis Chromophils and Chromophobes in the Adenohypophysis capillary Basophils Chromophils

19. pars tuberalis median eminence hypothalamus infundibulum (stalk) pars nervosa pars distalis pars intermedia Hypothalamus and Pituitary posterior anterior

20. Infundibulum Pars tuberalis Pituitary Pars tuberalis and portal veins Pituitary Pars tuberalis and portal veins Portal veins

21. pars tuberalis median eminence hypothalamus infundibulum pars nervosa pars distalis pars intermedia Hypothalamus and Pituitary posterior anterior

23. Hypophyseal portal system 1 2 3 4

24. Infundibulum Pars tuberalis Pituitary Pars tuberalis and portal veins Pituitary Pars tuberalis and portal veins Hypophyseal portal veins

25. Pituitary hormones and their target organs

26. Thyroid Gland

27. Thyroid gland Parathyroid gland Parafollicular cell Follicular cell Colloid Oxyphil cell Chief cell Thyroid and parathyroid glands

28. CT lobule F Two thyroid lobules separated by CT septum

29. Thyroid Follicles capillaries Follicular cells thyroglobulin Basement membrane

30. A.Synthesis and iodination of thyroglobulin B.Release of thyroxine (T3 and T4) A.Synthesis and iodination of thyroglobulin B.Release of thyroxine (T3 and T4) AB

31. TRH TSH T3/T4 Iodine TRH Excess TSH Low T4 Iodine Negative feedback Low Negative feedback hypothalamus Iodinedeficiencygoiter

32. Iodine deficiency goiter goiter

33. Parafollicular cells in the thyroid

34. Inhibits osteoclasts stimulates osteoclasts Action of calcitonin and PTH in blood calcium homeostasis Action of calcitonin and PTH in blood calcium homeostasis

35. Thyroid Parathyroid Parathyroids are situated on the posterior surface of the thyroid gland Parathyroids are situated on the posterior surface of the thyroid gland

36. Parathyroid Parathyroid and thyroid glands

37. Cells of the parathyroid Oxyphil cells Chief cells

38. Inhibits osteoclasts stimulates osteoclasts Interaction of calcitonin and PTH in blood calcium homeostasis Interaction of calcitonin and PTH in blood calcium homeostasis

39. Adrenal Gland

40. Z. glomerulosa Z. fasciculata Z. reticularis Medulla Capsule Cortex Adrenal

41. Capsule Z. glomerulosa Z. fasciculata Z. reticularis Medulla Mineralocorticoid s (e.g. aldosterone) Sex hormones e.g. DHEA Adrenaline Noradrenaline Hormones cap Glucocorticoids e.g. cortisol Preganglionic sympathetic terminal

42. Z. glomerulosa Z. fasciculata Z. reticularis Medulla Capsule Cortex Adrenal

43. Capsule Z. glomerulosa Z. fasciculata Z. reticularis Medulla Mineralocorticoid s (eg. aldosterone) Glucocorticoid s (eg cortisone) Sex hormones (eg DHEA) Adrenaline Noradrenaline Hormones cap Preganglionic sympathetic neuron

44. Chromaffin cells Chromaffin cells Postganglionic parasympathetic neurons Postganglionic parasympathetic neurons Cells of the adrenal medulla

45. Capsule Subcapsular arterial plexus Fenestrated sinusoids Medullary artery Medullary vein Adrenal Blood Supply Z. glomerulosa. Z. fasciculata. Medulla. Z. reticularis.

46. Arterial and Venous blood in Adrenal

47. Pancreas

49. Islet of Langerhans in Pancreas IsletIslet Acinar cells

50. Cells and hormones of the pancreatic islets  -cells secrete insulin (causes decrease in blood glucose)  -cells secrete glucagon (causes breakdown of glycogen and increase of blood sugar) 3.  -cells secrete somatostatin (has both paracrine [inhibits release of insulin and glucagon] and endocrine effects [reduces motility of smooth muscle of gut]) 4. G-cells secrete gastrin (stimulates release of HCl from parietal cells of stomach 5. PP-cells secrete pancreatic polypeptide (inhibits exocrine secretion of pancreatic enzymes) secretion of pancreatic enzymes)

51. C’est tout

52. GUTLIVER TYPES OF MICROCIRCULATION Typical arrangement Venous Portal system Arterial portal system

53. Hormone production and release by the neurohypophysis ( pars nervosa) ( pars distalis)