1. Reproductive Cycle
Ch. 28-3

2. Female Reproductive Cycle
Ovarian Cycle – events in the ovaries that occur during and after the maturation of an oocyte
Menstrual Cycle – changes in the endometrium (lining) of the uterus to prepare for the arrival of a fertilized ovum that will develop until birth
Female reproductive cycle includes both of these

3. Hormones of Cycles Gonadotropin-releasing hormone (GnRH) Estrogens
Secreted by hypothalamus
Stimulates release of FSH and LH
Stimulate release of egg from ovaries
Estrogens
Secreted by ovaries
Promote development of sex characteristics
Progesterone
Prepare and maintain endometrium for implantation
Prepare mammary glands for milk secretion

4. Hormones of Cycles Relaxin Inhibin
Relaxes the uterus by inhibiting contractions
Increases flexibility of pubic symphysis
Helps dilate cervix
Inhibin
Secreted after ovulation
Inhibits secretion of FSH and LH

6. Tortora & Grabowski 9/e 2000 JWS
Hormonal Changes
Tortora & Grabowski 9/e 2000 JWS

7. Summary Cycle is counted from 1st day of last period
Menstruation lasts 4-5 days
Proliferative phase (13 days)
Endometrium fills will tissue and blood
Ovulation occurs around day 14
Secretory phase (10 days)
If egg is fertilized, tissue stays to care for fetus
If egg is not, menstrual phase begins again

8. Birth Control
Oral contraceptives (the pill) – inhibits FSH and LH from being released, ovulation doesn’t occur, no egg for fertilization – close to 100% effective
“morning-after-pill” – causes shedding of lining (induces period) to prevent implantation
IUD – prevent implantation in uterus by changing lining
Spermicides – kill sperm, more effective with use of condom or diaphragm

9. Birth Control
Barrier methods – prevent sperm from getting into uterus (condoms, diaphragm); also helps protect against STD’s
Periodic Abstinence – couple learns “cycle” and abstains during that time