REPRODUCTIVE SYSTEM: FEMALE

I.   INTRODUCTION
–  both male and female reproductive systems consist of:

1)  gonads (primary sex organs):  testes in the male, ovaries in the female
2)  accessory reproductive organs:  uterine tubes, uterus, vagina, external genitalia, and mammary glands

– broad ligament: layer of peritoneum that “drapes” over uterus and uterine tubes

–  at puberty: anterior pituitary releases FSH (follicle stimulating hormone) and LH (Luteinizing hormone)

II.  OVARY (Plural: ovaries)

–  functions:    

A.  External Anatomy:
–  each is oval shaped
–  within pelvic cavity
–  they attach to posterior of the broad ligament

B.  Internal Anatomy:
–  outer cortex and an inner medulla

- medulla contains blood vessels

–  cortex contains ovarian follicles

–  ovarian follicles consist of an oocyte (egg) plus follicle (or granulosa) cells that surround the oocyte

–  different kinds of follicles:

1)  primordial follicle:  primary oocyte surrounded by a single layer of flattened follicle cells

2)  primary follicle:  primary oocyte surrounded by one or more layers of cuboidal follicle (granulosa) cells

3)  secondary follicle:  primary oocyte + follicle (granulosa cells) + antrum (fluid-filled space)

4)  vesicular  follicle:  secondary oocyte + follicle (granulosa) cells + very LARGE antrum

ovulation:  process where a secondary oocyte is expelled from the ovary

–  other structures in the cortex:

1)  corpus luteum: the ruptured follicle that underwent ovulation
*  yellowish
*  function:

2)  corpus albicans:  degenerated corpus luteum
*  white CT scar

III. OOGENESIS (oocyte formation)
–  before birth (during fetal period):
*  ovary contains oogonia (oocyte “stem cells”)
**  oogonia contain 23 pairs of chromosomes

*  primary oocytes are oogonia that start the process of Meiosis
**  meiosis “arrested” at Prophase I

*  so before birth, the ovary will contain primarily primordial follicles (which have primary oocytes in them)

–  during childhood:  ovary inactive

–  at puberty: anterior pituitary secretes FSH (follicle stimulating hormone) and LH (luteinizing hormone): stimulate follicle development

–  each month from puberty to menopause (when ovulation/menses cease entirely): 
*  about 20 primordial follicles will “mature” into primary follicles

*  some primary follicles become secondary follicles

*  one of these secondary follicles will become “dominant” and will fully mature into a vesicular follicle

*  in the vesicular follicle, the primary oocyte will complete Meiosis I, but gets stopped at Metaphase II of meiosis

**  at this point, you now have a secondary oocyte!

*  a peak in LH levels at about day 14 (of a 28-day ovarian cycle) will induce ovulation

**  the structure expelled is a secondary oocyte

**  this oocyte is still suspended at metaphase II - it will not complete meiosis UNLESS it becomes fertilized by a sperm!

*  after the secondary oocyte is expelled, FSH and LH levels decline

**  ruptured follicle will become a corpus luteum

**  corpus luteum eventually becomes a corpus albicans

IV.  UTERINE (FALLOPIAN) TUBES
–  paired tubes that attach to the uterus
–  each uterine tube is close to (but not attached to) the ovary!

–  at the ends of each tube are fimbriae:

–  Functions:

1)

2)

V.   UTERUS
–  single, pear-shaped organ, in pelvic cavity
–  function:

*  when a fertilized egg doesn’t implant, it is the site for menstruation (shedding of part of the uterine wall)

A.  Gross Anatomy:
–  cervix

B.  Microscopic Anatomy:

1)  Perimetrium:  outermost layer
*  visceral peritoneum + areolar CT

2)  myometrium:  middle layer
*  THICKEST layer
*  3 layers of smooth muscle

3)  endometrium:  innermost layer
*  highly vascular
*  columnar epithelium and CT
*  fertilized oocyte implants here
*  it is subdivided into 2 sublayers:

a)  basal layer:  the deeper layer immediately adjacent to the myometrium
*  this is a permanent layer

b)  functional layer:
*  it will grow and develop during the ovarian cycle
*  if a fertilized oocyte doesn’t implant, this layer is shed during menstruation (menses)

–  so WHY does menstruation occur?

VI.  VAGINA
–  muscular tube that opens to the outside
–  lies behind bladder, and in front of rectum
–  functions: 

1)

2)

VII. EXTERNAL GENITALIA (VULVA)

A.  Mons Pubis:  fatty, rounded area - covered with pubic hair

B.  Labia Majora (2): two elongated, skin folds between legs - covered with pubic hair
* homologous to:

C.  Labia Minora (2): thin, hairless skin folds
*  between the labia minora are:

1)  urethral orifice (opening):

 

2) vaginal orifice (opening):

3)  openings for the greater vestibular glands:
*  homologous to:

*  function:

4)  clitoris: anterior to the urethral orifice
*  homologous to:

*  contains two columns of erectile tissue (corpora cavernosa)

VIII. MAMMARY GLANDS (Breasts)
–  apocrine glands

–  each mammary gland has glandular tissue (produces milk), adipose tissue, and ligaments to connect/support it to the thoracic wall

–  function:  to produce milk for a baby

*  lactation = breast milk production

–  prolactin: stimulates milk production

–  oxytocin: RELEASES milk in response to a stimulus (baby suckling/crying)

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