Tuesday!!!! 3/29

1. Tuesday!!!! 3/29 • Explain how hormones control the menstrual cycle in human females. • (Total 8 marks)

2. FSH stimulates the development of follicles; • FSH stimulates estrogen secretion (by the developing follicle); • estrogen stimulates the repair of the uterus lining; • estrogen stimulates LH secretion; • LH causes ovulation; • LH causes the development of the corpus luteum; • LH causes secretion of progesterone; • progesterone causes thickening of the uterus lining / prepares uterine lining for implantation; • progesterone / estrogen inhibits secretion of LH / FSH; • falling progesterone levels at the end of the cycle allow FSH production / menstruation; • feedback control;

3. 6.6Reproduction

4. 6.6.1 Draw and label diagram of the adult male reproductive system. • Testes- in scrotum • Epididymis • Vasdeferens- from epididymis • Seminal vesicle- on vas deferens prior to prostate gland • Prostate gland- below bladder where urethra and vas deferens join • Urethra- from bladder through penis • Bladder • Penis- with erectile tissue

6. 6.6.1 Draw and label diagram of the adult female reproductive system. • Ovary w/follicles • Oviduct- showing fimbria • Uterus- showing endometrium (inner lining) • Cervix- between uterus & vagina • Vagina- • Vulva- • Clitoris- • Bladder- • Urethra-

8. 6.6.2 Outline the role of hormones in the menstrual cycle, including • From puberty to menopause • 28 days • Ovulation (release egg for possible fert.) • Endometrium becomes highly vascular –support implantation; breaks down if no impl. • Menstrual bleeding (sign of no pregnancy) • FSH (follicle stimulating hormone), • LH (luteinizing hormone), • estrogen, & • progesterone.

9. 6.6.2 Outline the role of hormones in the menstrual cycle, including • FSH (follicle stimulating hormone) & LH (luteinizing hormone) •  prod/secretion of E (follicle cells) • Production of Graafian follicles (follicle cells + oocyte, maturing) • Ovulation (release of oocyte & inner ring of follicle cells)

10. 6.6.2 Outline the role of hormones in the menstrual cycle, including • Estrogen • Bloodstream  endometrium •  vascularization of uterus • If no pregnancy, CL breaks down,  in P and E  vasc breaks down  menstrual bleeding • Progesterone • After ovulation, outer ring foll cells remain in ovary, secrete P • Maintains vascular endometrium (for implantation) • Mitosisfill in “ovul. wound” w/CL, it produces P for ~14d post-ovulation • If no pregnancy, CL breaks down,  in P and E  hypothal  GnRH  FSH/LH

11. HYPOTHALAMUS GnRH PITUITARY GLAND (ANT.) - feedback - feedback FSH LH OVARIES Progesterone (after ovulation) Estrogen While E&P high, no more LH&FSH produced, no more foll mature. ENDOMETRIUM OF UTERUS (INCREASED VASCULAR TISSUE)

13. What about birth control pills??? • E & P in pills • High levels maintained • Hypothal doesn’t produce GnRH • Pituitary doesn’t produce FSH, LH • No new Graafian follicles • Ovulation doesn’t occur

14. http://www.pbs.org/wgbh/amex/pill/sfeature/sf_cycle.swf

15. 6.6.3 Annotate a graph showing hormone levels in the menstrual cycle, illustrating the relationship between changes in hormone levels and ovulation, menstruation and thickening of the endometrium.

18. 6.6.4 List three roles of testosterone in males. • pre-natal development of male genitalia • development of secondary sexual characteristics @ puberty • maintenance of sex drive throughout lifetime

20. Natural Fertilization Process: • In oviduct, 24-48 h post-ovulation • Several days to travel to uterus (& several mitotic divisions) • Implantation • Problems: • Low sperm count or impotence in male • Ovulation complications • Blockage of oviduct

21. 6.6.5 Outline the process of in vitro fertilization (IVF). • Woman-injections FSH ~10d • Many Graafian follicles develop • Harvest several oocytes (surg.) • Man-sperm donation • Eggs & sperm mixed in separate culture dishes • Microscope  which ova fertilized, normal healthy embryo(s) developing • 2-3 introduced to uterus for implantation • $$$$$$$!!! • Use several embryos to decrease failure rate & need to repeat procedure • Healthy, unused embryos frozen, can be used for later implantation if necessary

23. 6.6.6 Discuss the ethical issues associated with IVF. • For: • Enables couples (otherwise unable) to have a family • Visibly unhealthy embryos can be eliminated from consideration for implantation • Genetic screening possible prior to implant., can eliminate chance of passing on gen diseases • IVF technology will advance, lead to further benefits in repro biology Against: • Cultured embryos not implanted are frozen or destroyed • Legal issues: uses of frozen embryos if couple divorces • Genetic screening embryos could lead to society choosing desirable characteristics • Repro problems can be passed on genetically (IVF bypasses natural selection, genetic freq of the problem) • Multiple births (& problems) more frequent than w/natural conception

24. 6.6.6 Discuss the ethical issues associated with IVF. TOK: • Potential risks in drug treatments woman is given • Concerns about artificial selection of sperm and injection of them into the egg that occurs with some IVF protocols • Natural selection of sperm with consequent elimination of unhealthy ones is bypassed • Evidence that there are higher rates of abnormality in the offspring as a result