Endocrine system

1. Endocrine system

2. Endocrine system • 3 types of regulatory molecules: • 1) Hormones: regulatory chemicals secreted into blood by endocrine gland • Work only on ____________ cells (those that can be influenced by its “message”)

3. Endocrine system • 3 types of regulatory molecules: • 2) Neurohormones: hormones released into blood by some neurons

4. Endocrine system • 3 types of regulatory molecules: • 3) Paracrine hormones: chemicals secreted by cells of organ that influence others in organ (not transported by blood)

5. Endocrine system 3) Paracrine hormones. Example: prostaglandins. Derived from cholesterol • Many functions: one is to promote inflammation (pain, fever) • Aspirin, ibuprofen, celebrex: inhibit prostaglandin production but vary in side effects (some can cause _____________ in small intestine, etc)

6. Endocrine system • Hormone chemistry: • 1) polypeptides: chains of amino acids (<100 aa’s long). Ex, insulin, ADH (antidiuretic hormone) Structure of insulin

7. Endocrine system • Hormone chemistry: • 2) glycoproteins: long polypeptide (>100 aa’s long) with carbohydrate attached. Ex, FSH (follicle stimulating hormone) and luteinizing hormone (LH)

8. Endocrine system • Hormone chemistry: • 3) amines: variations of the amino acids tyrosine and tryptophan. Ex, adrenalin, thyroxine. tyrosine tyramine adrenaline tryptophan

9. Endocrine system • Hormone chemistry: • 4) steroids: lipids derived from cholesterol. Ex, testosterone, estradiol, progesterone cholesterol

10. Endocrine system • Most hormones are hydrophilic (water soluble) • Recall from BIOL 1020 that cell membranes are hydrophobic • This means that water-soluble molecules can’t cross them. • How signal transmitted into cells? By __________ protein in membrane

11. Endocrine system • Hydrophilic hormone example • Hormone binding temporary, detaches and can travel to another cell and bind again (and again) • 1 hormone molecule can signal many ________!

12. Endocrine system • Hydrophobic hormones are steroids and thyroxine • They penetrate membranes and bind to receptors inside cell

13. Endocrine system • Example hydrophobic hormones are steroids (testosterone, estradiol) and thyroxine

14. Endocrine glands • Pituitary gland: located under brain • Has two portions: anterior (in front) and posterior (in rear). Each portion with different embryonic origin and very different functions

15. Endocrine glands • Posterior pituitary gland hormones • Antidiuretic hormone (ADH): influences water reabsorption in kidneys. • Note: alcohol consumption inhibits ADH secretion (so frequent need to _______________).

16. Endocrine glands • Posterior pituitary gland hormones • Oxytocin: stimulates milk “let-down” in nursing mothers (milk secreted into ducts in breast). Also stimulates uterine contractions during childbirth.

17. Endocrine glands • Anterior pituitary gland hormones • growth hormone (GH): stimulates growth of bone and muscle • Too much: gigantism 8 feet 11 inches, 485 pounds. Lived 22 years, never stopped growing!

18. Endocrine glands • Anterior pituitary gland hormones • growth hormone (GH): stimulates growth of bone and muscle • Too little: pituitary dwarfism

19. Endocrine glands Anterior pituitary gland hormones • follicle stimulating hormone (FSH) and luteinizing hormone (LH): involved in menstrual cycle in females and sperm production in males

20. Endocrine glands Anterior pituitary gland hormones • follicle stimulating hormone (FSH) and luteinizing hormone (LH): involved in menstrual cycle in females and sperm production in males • prolactin (PRL): stimulates milk production in mammals

21. Endocrine glands • Thyroid gland: in throat just under larynx

22. Endocrine glands • Thyroid gland hormone (main): • Thyroxine: helps set body’s metabolic rate • Too little: ______________. Often severe retardation.

23. Endocrine glands • Parathyroid glands: On thyroid • Make parathyroid hormone (PTH): vital to maintain Ca+2 level in body • Can influence Ca+2 reabsorption in kidney, Ca+2 release from bone, and absorption of Ca+2 in small intestine.

24. Endocrine glands • Adrenal glands: Located on kidneys

25. Endocrine glands • Adrenal glands • Located on kidneys • Have cortex (outer) and medulla (inner) portions

26. Endocrine glands • Adrenal glands • Medulla: secretes ______________ when stimulated by nerve system. Part of “fight or flight” response. Increase heart rate, blood pressure, blood glucose. Reduced blood flow to skin and digestive system

27. Endocrine glands • Adrenal glands • Cortex: secretes corticosteroids. Involved in _________ balance, glucose balance, etc.

28. Endocrine glands • Pancreas • Located below liver in abdomen

29. Endocrine glands • Pancreas • Recall Islets of Langerhans. Make insulin and glucagon. Together, regulate glucose in blood.

30. Endocrine glands • Gonads (testes and ovaries)

31. Endocrine glands • Gonads (testes and ovaries) • Make steroid sex hormones • Testosterone, estradiol, progesterone (discussed)

32. Endocrine disruptors • Chemicals from environment that can interfere with endocrine system • Chemical structures similar to those of some hormones • Examples: pesticides, herbicides, etc.

33. Endocrine disruptors • Ex, Lake Apopka, Florida • 1980: chemical spill of pesticide DDT • Affected development of male alligators (lower testosterone levels, smaller __________ size, anatomical defects)

34. Endocrine disruptors • Human concerns: • Puberty of females coming earlier • Many possible causes, but endocrine disruptors may be involved

35. Endocrine disruptors • Ex, Michigan 1973 • Chemical called PBB accidentally mixed into cattle food • Meat and dairy products reached 4,000 people • Daughters of women exposed surveyed in late 1990s • Menstruation started ______ years earlier in daughters of exposed women