The Reproductive System - Female

Describe the macroscopic and microscopic anatomy of the ovaries. LT# 4 Lie in shallow depressions on each side of pelvic cavity (homologous to testes) Outer cortex & inner medulla Contains many saclike follicles containing oocytes 2,000,000 at birth K by puberty About 400 reach maturation

Ovarian anatomy cont’d Follicular development = 1º follicle  2º follicle  Graafian follicle 1º follicle has 1º oocyte (46 chromosomes) & ÷ meiotically to become 2º oocyte (23) w/one cell getting most of cytoplasm

Ovarian anatomy cont’d 2º oocyte is pushed to one side of follicle & becomes Graafian follicle under pressure & balloons out on ovarian surface Wall bursts, egg is released = ovulation Egg surrounded by corona radiata (follicular cells

Genital tract Uterine (fallopian) tubes extend from uterus to ovaries (homologous to vas deferens) Uterus (womb) – pear sized, thick walled muscular organ (together w/vagina & clitoris homologous to penis) vagina (birth canal) – folded fibro muscular wall

Describe the ovarian and uterine cycles. LT#5 28 days: 1-13 follicle develops & secretes estrogen Day 14 = ovulation corpus luteum secretes progesterone to prepare womb & degenerates if no pregnancy

Describe the ovarian and uterine cycles. LT#5 Effects of hormones on uterus Days 1-5 endometrium disintegrates due to low hormone levels Days 6-13 ↑ estrogen (ovarian follicle) causes endometrium to thicken 14 – ovulation ↑ estrogen (c. luteum) causes endometrium to double No pregnancy = low hormones & disintegration

Temporal constraints for accomplishing fertilization. What is fertilization? Fertilization is when a sperm fuses with an egg to form a zygote Temporal (time) constraints for accomplishing fertilization are Oocyte is viable for 12 to 24 hrs Sperm is viable for 24 to 72 hrs Coitus must occur no more than 3 days before ovulation and 24 hrs after ovulation

Speculate as to the adaptive significance of orgasm. Fertilization happens in fallopian tubes w/12-24h window Advantageous for sperm to get through to f.t. asap Male orgasm = contraction & relaxation that propels sperm forward, prostaglandins cause uterine contractions

Females have 2 types of orgasms During a clitoral orgasm, the vagina becomes longer, and it causes a pocket to be formed beneath the uterus. (sperm holding tank) During a vaginal orgasm, the uterus drops lower and shortens the vagina. (shorter sperm path) Stimulation of both the vagina and clitoris can cause a blended orgasm, the third type of orgasm.

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Discuss the anatomical & physiological changes that occur in the reproductive system and we age. Males – testosterone production diminishes > 50  enlargement of prostate Sperm production declines w/age Impotency increases w/age due to degenerative vascular changes of penis Reduced erection until close to ejaculation

females Menopause = ovarian & uterine cycles cease (45-55) Atrophy of secondary sex characteristics Wrinkling Osteoporosis Higher risk for heart attack