Chapter 36

2. Chapter 36 Integration & Control: The Endocrine System

3. Endocrine System • Works w/ nervous system to control all functions of the body • Endocrine glands • Ductless • Hormones • Pineal, pituitary, thyroid, pancreas, etc. • Exocrine glands • Ducts • Non-hormones • Salivary, sebaceous, sweat

4. Endocrine System • Hormones • Chemical signals • Carried in bloodstream • Affect cells away from gland • Homeostatic

5. Hormones • Positive feedback • Increase in hormone stimulates further secretion • Uterine contractions stimulate oxytocin • Negative feedback • Increase in hormone inhibits further secretion • Thyroid Stimulating Hormone produces T3/T4

6. Hormones • Peptide hormones • Water soluble • Mostly protein • Attach to cell membrane • Trigger secondary messenger within cell • Epinephrine, oxytocin, antidiuretic hormone (ADH), etc.

7. Hormones • Steroid hormones • Water insoluble • Cholesterol-based • Cross into cell • Bind to receptors in cytoplasm or nucleus • Estrogen, testosterone, cortisol, etc.

8. Pituitary Gland • “Master Gland” • Associated with & directed by hypothalamus • Posterior & Anterior lobes

9. Pituitary Gland • Posterior Lobe • Stores secretions from hypothalamus • Oxytocin • Uterine contractions • Milk “let down” • ADH • Conserves water • Kidney tubules reabsorb water

10. Pituitary Gland • Anterior Lobe • Prolactin • Breast development • Stimulates & sustains milk production

11. Pituitary Gland • Anterior Lobe • Growth Hormone (GH) • Stimulates body cells to grow & divide • Mostly young bones & muscles • Thyroid-Stimulating Hormone (TSH) • Thyroid gland growth • Secretion of thyroid hormones • Adrenocorticotropic Hormone (ACTH) • Adrenal gland growth • Secretion of cortisol from adrenal gland

12. Pituitary Gland • Anterior Lobe • Follicle-Stimulating Hormone (FSH) • Stimulates estrogen secretion • Stimulates egg production (females) • Stimulates sperm production (males) • Luteinizing Hormones • Stimulates ovulaton • Stimulates progesterone secretion (females) • Stimulates testosterone secretion (males)

13. Pituitary Gland • Anterior Lobe • Melanocyte-Stimulating Hormone (MSH) • Stimulates melanocytes in skin • Increases during human pregnancy • Increases in amphibians in dark location

14. Pituitary Gland • Anterior Lobe • Endorphins • Natural pain-killers • Sense of well-being • Strenuous exercise, excitement, orgasm • “Runner’s High”

16. Thyroid Gland • Regulates speed of all basic cellular processes • Energy burning • Protein synthesis • Thyroxine (T4), Triiodothyronine (T3) • Controls metabolism • Affects growth • Calcitonin • Lowers blood calcium levels • Increases deposit of calcium in bones

17. Parathyroid Gland • Calcium metabolism • Parathyroid Hormone (PTH) • Breaks down bone to release calcium • Increases intestinal absorption • Increases kidney retention

18. Adrenal Gland • Cortex • Produces corticosteroids • Mineralocorticoids • Aldosterone—controlselectrolytes through kidneys • Glucocorticoids • Cortisol—“stress hormone” • Increases blood pressure & blood glucose • Suppresses immune system • Andgrogens • Testosterone • Cause masculine traits

19. Adrenal Gland • Medulla • Hormones released under stress • Controlled by sympathetic nervous system • Epinephrine • 80% of medullary hormones • Increases heart rate, blood pressure, and blood sugar • Increases sympathetic effects • Norepinephrine • 20% of medullary hormones • Maintains blood pressure

20. Thymus Gland • Large in infant • Increases until puberty • Shrinks until adulthood • Thymosin • Normal development of immune system

21. Pineal Gland • Melatonin • Regulates biological clock • Regulates sleep cycle • “Lower” vertebrates, cells resemble photoreceptor cells of eye • May be triggered by light

22. Pancreas • Endocrine & exocrine • Digestive enzymes • Glucagon • Breaks down glycogen to glucose • Frees stored glycogen in liver • Insulin • Lowers blood glucose • Increases uptake of glucose into body cells

23. Ovaries • Estrogen • Female sexual characteristics • Sperm maturation & libido in males • Progesterone • Prepares uterus for egg implantation • Regulates menstrual cycle

24. Testes • Testosterone • Male sexual characteristics • Sexual behaviors • “Male” behaviors • Aggression • Territoriality

25. Other organs • Kidneys • Erythropoietin—stimulates red blood cell production • Skin • Calcidiol—inactive form of vitamin D • Skeletal muscle • Thrombopoietin—stimulates platelet formation • Adipose (fat) • Leptin—decrease appetite, increase metabolism

26. Hormonal Imbalances • Hypersecretion of GH • Gigantism—in children • Acromegaly—in adults

27. Hormonal Imbalances • Hyposecretion of GH • Pituitary dwarfism—children, slow bone growth

28. Hormonal Imbalances • Hypothyroidism • Fatigue • Thin, brittle hair & nails • Weight gain • Poor muscle tone • Goiter • Inflammation of thyroid gland • Can be due to iodine deficiency

29. Hormonal Imbalances • Hyperthyroidism • Weight loss • Ravenous appetite • Irritability, anxiety • Fatigue • Hyperactivity • Graves’ disease • Protrusion of eyes • Edema (fluid accumulation) • Thickening of skin • Goiter

30. Hormonal Imbalances • Diabetes insipidus • Deficiency of ADH • Increased urine output • Chronic dehydration risk • Diabetes mellitus • Deficiency of insulin • High blood glucose levels • Type I—usually before age 20, pancreas cells stop producing, autoimmune • Type II—usually after age 40, insulin levels normal, cells don’t respond to it

31. Hormonal Imbalance • Addison’s disease • Adrenal gland produces insufficient glucocorticoids • Low blood pressure • Darkening of skin • Vomiting, diarrhea • Mood, personality changes • Cushing’s disease • Overproduction of glucocorticoids • Weight gain • Thin skin, often stretched • Muscle weakness • Hirsuitism (horses & humans) • Hyperglycemia