1. May 2, 2014 – Chemical signals and hormones IV Announcements: - Final is NOT CUMULATIVE* - In lecture review session (Wed. May 7) - TA led review session (10am – 12pm, Wed. May 14, 151 Everett Lab 1.Pre-lecture quiz 2.Review of stress responses 3.Hormone-mediated physiological tradeoffs 4.Interactions between the HPA and HPG axes 5.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 Tradeoffs Interactions between stress, reproduction and immune function

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

10. Testosterone treated Control Territory sizeLargerSmaller Singing frequencyHigherLower # of aggressive interactionsHigherLower Number of matingsHigherLower Number of offspringHigherLower Offspring qualityLowerHigher SurvivalLowerHigher

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

12. Montane Urban Breeding seasonShorterLonger AggressivenessHigherLower Male parental investmentHigherLower TestosteroneHigherLower CortisolHigherLower Stress responseHigherLower

13. Hormone-mediated Tradeoffs Interactions 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 Males Females

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

23. Figure 48-13-2 Ovulation Pituitary hormone cycle Ovarian cycle Follicle growth FOLLICULAR PHASE Corpus luteum degeneration LUTEAL PHASE FSH LH Hormone levels Days 07142128

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