Organs of the Reproductive Tract:
     

1.  Ovaries - Produce egg cells and hormones,
     
2.  Uterine tubes - Transport ova to uterus.
     
3.  Uterus - Site of most embryological development.
     
4.  Vagina - Receptacle for penis and spermatozoa.
                                             
5.  Vulva - Outer folds covering the external urogenital region.
     

I Ovaries 
     

 A. Paired, almond-shaped organs in the upper pelvic cavity.
     
 B. Held in place by:
     
  1. Mesovarian - an outpocketing of the broad ligament,
     
  2. Ovarian ligament - anchors ovaries to uterus.
     
  3. Suspensory ligament - attaches ovaries to pelvic wall.
     
 C. Histology
    1. Germinal epithelium - simple cuboidal epithelium covering the
    free surface of ovary. It is the source of ovarian follicles.
    2. Tunica albuqinea - collagenous connective tissue just below the
    germinal epithelium.
    3. Stroma - interior of ovary consisting of an outer dense connective
    tissue region called the cortex. Ovarian follicles form here. Surrounded
    by the cortex is an inner region of looser connective tissue called
    the medulla,
    4. ovarian follicles - the egg cell with its surrounding tissues,
    The most mature stage is called the Graafian follicle, It secretes
    estrogen.
    5. Corpus luteum - developes from a ruptured follicle after ovulation.
    of the egg, It produces estrogens, progesterone and relaxin. After
    its inactivation at the end of a menstrual cycle, it becomes a
    corpus albicans (essentially scar tissue)
     

    II Uterine Tubes
     

    A. Extend laterally from uterus for about 4", and enveloped by folds
    of the broad ligament, the tubes transport egg cells to the uterus.
     

    B. The major regions of the tube are:
    1. The Infundibulum - funnel-shaped, distal end of uterine tube
    with finger-like fimbriae surrounding ovary,
    2. The Ampulla - widest, longest portion of tube, it is usually the
    site of fertilization.
    3. The Isthmus - short, narrow, thick walled portion that joins the
    uterus.
     

Histology - three layers
     

    1. Mucosa - ciliated, columnar cells
     

    2. Muscularis - inner, circular and outer longitudinal smooth muscle.
    

    3. Serosa - Outer, tough serous membrane,
     

Fertilization
     

    After ovulation, the egg cell may be fertilized in the pelvic
    cavity and implant itself on the surface of a visceral organ (pelvic
    implantation). It will not survive here because of inadequate blood 
    supply. Normally, peristaltic contractions of smooth muscle and
    ciliary waves of the epithelium move the egg through the uterine tube.
    Usually fertilization occurs in the ampulla if viable sperm are present.
    Sometimes implantation occurs here also.  This is called an ectopic or a tubal pregnancy.  Since
    there is an adequate blood supply for some development, the pregnancy
    must be terminated before the tube bursts. Normally, the blastocyst,
   (early embryonic stage) reaches the uterus in 7 days.
     

    III Uterus
     

    A, Site of menstruation, implantation of the fertilized ovum, develop-
    ment of fetus and labor. It is located between the rectum and urinary
    bladder.
     

    B. Regions:
     

       1. Fundus - dome-shaped superior area.
     

       2. Body - tapering, central portion,opening into vagina.
     

       3. Cervix - inferior, narrow portion opening into vagina.
     

       4. Isthmus - constricted,region between body and cervix.
     

    C. Posture - The uterus is normally flexed anteriorly (anteflexion)
    between the uterine body and the cervix, This posture is maintained by
    broad ligaments, uterosacral ligaments, cardinal ligaments and round
    ligaments. Retroflexion, a posterior tilting of the uterus, may make
    it difficult for conception to occur.
     
    D. Histology - Three layers of tissue.
     
    1. Perimetrium (serosa) - outermost layer continuous with the
    visceral peritoneum. 
     
    2. Myometrium - three layers of smooth muscle, it is thickest in the
    fundus and thinnest in the cervix. Produces the muscular contractions
    of labor.
     
    3. Endometrium - an inner mucous membrane consisting of two layers:
    a. stratum functionalis - next to the uterine cavity and shed
    during menstruation.
     
    b. stratum basalis - an underlying, permanent layer which produces
    a new functionalis after menstruation.

THE OVARIAN CYCLE

	At birth, all of the oocytes in the ovary are primary oocytes which have entered 
metaphase of the first meiotic division.  At puberty, on day one of the first menstrual cycle, 
a group of these oocytes begins to mature under the influence of the hormone FSH.  
At the earliest stage a single layer of smaller follicle cells begins to encircle 
the oocyte.  Grows to form a secondary then a tertiary follicle.  As it grows it 
releases larger amounts of estrogens and some progesterone.
	On day fourteen, the follicle ruptures releasing the oocyte with attending 
follicle cells into the peritoneal cavity. After day 14, the remnant of the follicle 
becomes transformed into the corpus luteum due to the action of the hormone LH. The 
corpus luteum produces increasing amounts of the hormone progesterone, as well as, 
smaller amounts of estrogens.

MENSTRUATION - THE MENSTRUAL CYCLE
     
   In females, the process of sex cell formation and gestation are
closely regulated by the endocrine system. Menstrual cycles that are
sequential and follow one another in succession are only found in
primates. In other mammals, the female is receptive to the male sexually
only during a brief period called estrous or heat.
     
MENSTRUAL CYCLE
     
  1. Menses -
    a. period of uterine bleeding which corresponds to the breakdown
    of the stratum functionalis of the endometrium.
     
    b. During this time blood levels of estrogen and progesterone are
    at a very low level.
     
    c. It lasts about seven days.
     
    d. Vaginal smears show an increase in the numbers of cornified
    squamous cells and a decrease in cuboidal cells.
     

  2. Proliferative stage 
    
    a. Rising levels in blood estrogen occur due to increased secretion
    from the follicles

    b.  Functional layer of the endometrium is reconstructed

    c.  This stage coincides with follicular development in the ovary.  
     
    d.  Vaginal smears show cornified cells almost exclusively.
     
    3. Secretory stage (Postovulatory stage)
    a. The corpus luteum develops from the remnant of the follicle in the
    ovary under the influence of LH.
     
    b. Corpus luteum begins to secrete progesterone. This hormone continues
    the buildup of the endometrium.  Endometrial glands enlarge and increase 
    their secretion of glycogen-rich mucous.

    c.  Arteries grow into the functional layer of the endometrium.
    
    d.  If no implantation of embryo occurs, progesterone levels drop sharply at 
    day 28 of cycle due to the secession of secretion from the corpus luteum. 
    This leads to the beginning of the next menstrual cycle.
     
    e. vaginal smears show fewer cornified cells and more cuboidal cells
    and leukocytes,