Major organs of female reproductive system:

1. Major organs of female reproductive system: Brain - releases GnRH Pituitary gland - secretes LH and FSH Ovary - produces eggs and sex hormones (estrogen and progesterone)

2. Ovary: located in pelvis has central core (medulla) and outer layer (cortex) germ cells stored in cortex highly vascular

3. Statistics regarding female germ cells Germ cells cannot regenerate after birth Most (99%) never ovulate but become atretic and die At birth, ~1 million eggs / ovary At puberty, ~100,000 eggs / ovary At 50+ years, nearly depleted Only ~400-500 ever ovulate

4. Female germ cells (egg, oocyte) Provides half of genetic material of new individual Supplies food and biochemical machinery for early development Surrounded in ovary by follicle Cell layers of follicle secrete factors which nurture, induce maturation of egg

5. Follicular development

6. Small group discussions: Mitosis vs. Meiosis What are homologous chromosomes? Sister chromatids? How many chromosomal replications occur during mitosis? Meiosis? How many cell divisions occur in each? How do chromosomes line up on mitotic / meiotic spindle? What’s a polar body?

7. Oogenesis At birth, primordial oocytes are arrested just prior to their first meiotic division Meiosis doesn’t resume until just before ovulation (due to LH surge) First meiotic division produces 2 germ cells of unequal size (secondary oocyte and polar body) Second reduction division doesn’t take place until sperm penetrates the egg

8. Role of LH in follicle development stimulates androgen production by thecal cells causes rupture of Graafian follicle during LH surge LH surge stimulates first meiotic division causes transformation of follicle to corpus luteum

9. Role of FSH in follicle development stimulates growth of follicles by acting on granulosa cells causes granulosa cell proliferation, secretion of factors necessary for maturation of egg

10. Oviducts Site of fertilization; transports embryo to uterus Internal lining has folds, ciliated cells Estrogen causes mucus secretion, ciliary beating, smooth muscle contraction Rarely, ectopic or tubal pregnancies occur Tied off during tubal ligation

11. Uterus size and shape of an inverted pear located between bladder and rectum consists of three layers: perimetrium (external surface) myometrium (thick layer of smooth muscle) endometrium (internal lining) Endometriosis = abnormal growth of endometrium

12. Cervix “cap” on uterus mucus glands produce plug Viscosity of mucus changes in response to estrogen pap smear Human papilloma virus cervical cancer is 8th most frequent cancer-caused fatality in women

13. Vagina copulatory organ and birth canal capable of stretching (facilitates childbirth and intercourse) environment is acidic (lactobacilli > lactic acid) prevents yeast infections acidic environment is hostile to sperm

14. External genitals (vulva) mons pubis labia majora labia minora clitoris urinary and reproductive systems remain separate in early years, vagina is covered by a ring of tissue called the hymen

15. Female sexual response Erectile tissue found in clitoris and labia Sexual arousal > vasocongestion Due to muscle contraction restricting flow through dorsal vein of clitoris orgasm = relief of vasocongestion, muscular contractions within the vagina and uterus

16. Female Circumcision Type I FC: clitoral hood is pricked or removed Type II FC: clitoris and most or all of the labia minora are removed Type III FC (pharonic circumcision, infibulation): clitoris, labia minora and most of labia majora removed; vulva wound is stitched closed