Chapter 28 Notes Continued The Femal Reproductive System

Chapter 28 Notes Continued
The Female Reproductive System

Physiology of the Ovary

1. Ovaries

almond -shaped in upper pelvic cavity
position maintained by ligaments
- broad ligament: anchor from uterus
- ovarian ligament: also anchored to uterus
- suspensory ligament: anchor to pelvic wall
cortex: outer germinal epithelium
             in fetal life: primary oocytes form and enter Meiosis I
             before birth: 1,000,000 in cortex
             at puberty: 40,000 of which 450 will develop in reproductive years
oogenesis
    - primordial follicle holds primary oocyte
    - primary follicle: oocyte surrounded by granulosa cells for nourishment
    - secondary follicle: a fluid-filled cavity forms with thecal cells at outermost boundary
                                    undergoes Meiosis I producing a secondary oocyte and polar body
    - Graafian follicle: oocyte in Meiosis II bursts from ovary "ovulation"
    - granulosa cells become the corpus luteum
    - with fertilization: secondary oocyte completes Meiosis II producing
      an ovum and a polar body and corpus luteum directs uterus
    - without fertilization: secondary oocyte degenerates and corpus luteum
      degenerates into the corpus albicans
medulla: no follicles, loose connective tissue and blood supply
female histology online
male and female compared online

Uterine Tubes and Uterus

2. Uterine tubes

funnel-shaped opening has finger-like projections called fimbriae
ova moves by fimbriae and cilia
fertilization in upper area the "ampulla" 25 hours after ovulation (textbook case)
fertilized ova moves across ciliated columnar epithelium for 7days

3. Uterus

4. Vagina

4" muscular tube between bladder and rectum
passage way for menstrual flow, delivery, and receptacle for penis
secretion of an acid mucus for lubrication and retardation of normal flora
vulva
- mons pubis: adipose tissue over pubic symphysis
- labia majora: two outer folds for protection, scrotum is homologue in male
- labia minora: two inner folds with orifices for urethra and vagina in center
- clitoris: erectile tissue anterior to labia minora

Hormones and Menstrual Cycle

5. Hormones

GnRH secreted by Hypothalamus
FSH secreted by anterior pituitary
- stimulates initial growth of follicles and their estrogen secretion
LH secreted by anterior pituitary
- stimulates late follicular development, ovulation, and corpus luteum
estrogen secreted by follicles
- distribution of adipose tissue
- width of the pelvis
- hair pattern
- larynx
- protein anabolism
- lower cholesterol levels in the blood
- inhibits release of GnRH, FSH and LH
progesterone and estrogen secreted by corpus luteum to prepare endometrium for implantation and mammary glands for milk secretion
relaxin secreted by corpus luteum to relax myometrium
oogenesis overview online

6. The Menstrual Cycle

Day 1-5	MENSTRUAL PHASE
Uterus:	stratum functionalis degenerates, arteries, veins, and glands open at surface discharging blood and tissue into the vagina
Ovaries:	about twenty primary follicles begin to develop into secondary follicles increasing their receptor sites for FSH and LH
Hormones:	estrogen and progesterone levels are low. Secretion of GnRH causes secretion of FSH and LH.

II.

Day 5-13	PREOVULATORY PHASE
Uterus:	cells of stratum basale undergo mitosis and begin repair of stratum functionalis with growth of surface epithelium, coiled arteries, and glands. (Proliferative Phase)
Ovaries:	secondary follicles grow rapidly; one develops into Graafian follicle, increases granulosa and thecal cells with a fluid filled cavity around the oocyte
Hormones:	FSH levels surge, developing follicles steadily increase estrogen level.

III.

Day 14-15	OVULATION
Uterus:	continues growth
Ovaries:	rise in LH stimulates the oocyte to complete Meiosis I, rupture of the Graffian follicle releases secondary oocyte and polar body
Hormones:	estrogen peaks and then falls, LH surges

IV.

Day 15-28	POSTOVULATORY PHASE
Uterus:	growth of arteries, glands, interstitial fluid of the functional layer in preparation for implantation of the fertilized egg. (Secretory Phase) Without fertilization and implantation, the corpus luteum degenerates, the hormone levels fall, and the endometrium begins to shrink.
Ovaries:	granulosa and thecal cells proliferate forming the corpus luteum; without fertilization the corpus luteum degenerates into the corpus albicans.
Hormones:	FSH and LH decrease, estrogen levels rise and fall at the end of the cycle, progesterone levels rise steadily until Day 22 and then fall.