May 2 , 2014 – Chemical signals and hormones IV Announcements: - Final is NOT CUMULATIVE*

1. May 2, 2014 – Chemical signals and hormonesIV • Announcements: • - Final is NOT CUMULATIVE* • - In lecture review session (Wed. May 7) • - TA led review session (10am – 12pm, Wed. May 14, 151 Everett Lab • Pre-lecture quiz • Review of stress responses • Hormone-mediated physiological tradeoffs • Interactions between the HPA and HPG axes • Sex hormones • * I will ask about recurrent themes (e.g. tradeoffs, negative feedback, etc.)

2. Stress response Operates via two interrelated systems: • SAM (Sympathetic-adrenomedullary) (Short Term Response) • HPA (hypothalamic-pituitary-adrenocortical) (Chronic Response).

3. SAM, adrenals, and epinephrine

4. Summary of the “fight or flight” response 1.) Increases in HR, BP, O2 consumption, blood glucose and fatty acid concentrations. 2.) Redirection of blood flow from the skin and digestive system toward heart, brain, and muscles. 3.) Relaxation pulmonary smooth muscle to dilate bronchi and increase O2 uptake. Take home messages: 1.) Short term stress responses are EXTREMELY beneficial over the short term. 2.) Prolonged stress responses can be harmful.

5. HPA axis and glucocorticoids • Adrenal cortex produces glucocorticoid hormones (GC). • Cortisol is most important human (GC), involved in regulating metabolism, immune response, and general homeostasis. • Elevated cortisol leads to: • Short term metabolism of fat stores into glucose • Increased hunger • Suppression of immune response; • Cardiovascular changes (e.g. increases in BP)

8. Hormone-mediated TradeoffsInteractions between stress, reproduction and immune function

9. Hormone-mediated Tradeoffs:Interactions between stress, reproduction and immune function

10. Testosterone treated Control

11. Hormone-mediated Tradeoffs:Interactions between stress, reproduction and immune function

12. Montane Urban

13. Hormone-mediated TradeoffsInteractions between stress, reproduction and immune function

14. HPG axis

15. Gonads • Male testes produce sperm cells • Female ovaries produce ova • Fertilization • Sperm cell + ovum = zygote • Sex chromosomes • Humans: XX = female, XY = male • Birds: ZW = female, ZZ = male • Many vertebrates lack sex chromosomes entirely

16. Sex Hormones– Released by Gonads • Androgens - e.g., testosterone (“male” hormones) • Estrogens - e.g., estradiol (“female” hormones) • Adult testes release more androgens and ovaries more estrogens • Progestins – also present in both sexes • progesterone prepares uterus and breasts for pregnancy • Adrenal cortex – also releases sex steroids

17. HPG axis &Reproductive System Males Also known as Leydig cells

20. Steps for spermatogenesis 1. GnRH released at hypothalamus -----> + section of FSH & LH at anterior pit. 2. a. FSH stimulates sertoli cells which stimulate spermatogenesis b. LH simulates Leydig cells which secrete testosterone Testosterone stimulates sertoli cells to stimulate spermatogenesis 3. a. testosterone has negative effects on GnRH b. testosterone has negative effects on LH & FSH c. Sertoli cells release inhibin which has negative effects on LH & FSH

21. HPG axis &Reproductive System Females Males

22. Secondary oocyte to oviduct 5.Degeneration of corpus luteum Figure 48-12 4. Ovulation Follicle cells Oocytes 3. Maturation of follicle 1. Formation of primary oocytes within follicles 2. Follicle growth

23. FOLLICULAR PHASE LUTEAL PHASE Ovulation Corpus luteum degeneration Follicle growth Ovarian cycle Figure 48-13-2 LH Hormone levels Pituitary hormone cycle FSH 0 7 14 21 28 Days

24. FOLLICULAR PHASE LUTEAL PHASE Ovulation Corpus luteum degeneration Follicle growth Figure 48-14 Follicles and corpus luteum secrete hormones Progesterone Estradiol Negative feedback on LH, FSH Negative feedback on LH Positive feedback on LH Ovarian hormones and pituitary hormones exert feedback on each other