Female reproductive system

I.  Introduction

- female reproductive system far more complex than male:

- sex organs:  ovaries;  produce eggs and sex hormones

- accessory ducts:  oviducts (uterine tubes), uterus, vagina

- external sex organs:  external genitalia, vulva

- mammary glands

II.  Anatomy of female reproductive system

A.  Ovaries

- paired, flank uterus on each side, almond-shaped

- X-section:  outer layer with forming gametes at different stages of development; inner layer region has blood vessels, nerves

- in cortex see ovarian follicles:  one or more layer(s) of cells surrounding an immature egg, oocyte

B.  Uterine tubes

- receive ovulated oocyte, provide site where fertilization occurs; very muscular walls

- fimbrae with cilia draw egg into tubes; peristalsis moves egg to uterus

- ectopic pregnancy -- fertilization and implantation in peritoneal cavity

C.   Uterus

- hollow, thick walled organ:  receives, retains, nourishes fertilized ovum

- size/shape of inverted pear; during pregnancy up to 60X original size

- layers:

D.  Vagina

-  thin-walled tube, 8-10 cm long, extends from vestibule to cervix

E.  External genitalia

-  collectively known as vulva

F.  Mammary glands:  

III.  Physiology of female reproduction

A.  Oogenesis

- note that in male gamete production begins at puberty; in female preparation for gamete production begins in fetus

-  thus at birth all of women's potential eggs formed:  of about 2 million follicles, at birth about 700,000 remain; by puberty about 300-400,000 left

B.  Ovarian cycle

-  follicular phase:  period of follicular growth, d1-d14

-  luteal phase:  period of corpus luteum activity, d14-d28

1.  follicular phase

2.  luteal phase:

  1. remaining follicular cells begin producing  progesterone, estrogen -- corpus luteum (CL)
  2. if fertilization occurs, the embryo produces human chorionic gonadotrophin (HCG) which maintains CL until placenta can kick in its own progesterone/estrogen production
  3. if fertilization does not occur, CL degenerates as no HCG

C.  Hormonal regulation of ovarian cycle

-  feedback inhibition patterns:

D.  Uterine cycle:  menstrual cycle, regulated by ovarian hormones

E. Extra-uterine estrogen effects

- female secondary sex characteristics:  increased deposits of subcutaneous fat, widening, lightening of pelvis; growth of axillary and pubic hair.

- maturation of reproductive structures

F.  Female sexual response

1.  excitement or arousal:

2.  Plateau  

- changes initiated during excitement phase intensify

3.  Orgasm

- at certain level of arousal, massive sympathetic discharge