Female Genital System — Anatomy

Figure 1 shows an outside view of the female genitalia, the way clinicians see it in the examination room, with the two lips of skin (Labia Majora and Minora) spread apart.  Note that there are three openings:

  • the Urethra, which leads to the Bladder for urination (Urinary Tract)
  • the Vaginal Opening to the Vagina, which leads to the Uterus (Genital Tract)
  • the Anus, which leads to the Rectum (Gastrointestinal Tract)

Other structures noted in Figure 1 are the Clitoris (for sexual stimulation), the Mons Pubis (area of skin with pubic hair), and the Perineum (area between the Vagina and Anus).  The Hymen, a protective membrane present at birth, tears and disappears by adulthood, often because of sexual intercourse, but even without (which is why it’s impossible to prove virginity by an exam).




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Figure 2 shows internal organs, from a side view:

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In the front, we see the Bladder right behind the pubic bone, with the Urethra leading out for urination (Urinary Tract).  In the back, there’s the Rectum, with the Anus opening to the outside, and the Large Intestine (not labeled) continuing up the Gastrointestinal Tract.  In between the Urethra and Anus, the Vagina leads up to the Cervix, which is the beginning segment of the Uterus, where a baby grows during pregnancy.  On each side of the Uterus there’s an Ovary, which produces the egg that travels down the Fallopian Tube to meet the sperm from a man.

Figure 3 shows a basic front view of the internal organs of the Female Genital System; Figure 4 shows the same organs in more detail:

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In Figure 4 we see the Vagina leading to the Cervix (the white inside it is semen with sperm).  The Cervix is the entry to the Uterus, which has a white egg inside it on our upper left (the woman’s right, since this is a front view).  The Uterus consists of a lining called the Endometrium, and thick muscle called the Myometrium (“Fundus” in the figure is just a name for the top of the Uterus).

Off on each side is an Ovary and a Fallopian Tube.  Here the Right Ovary, cut in half, shows the follicle that the egg had come out of (it’s really microscopic, but shown larger here just to illustrate).  Every month from a woman’s early teens to late 40’s or early 50’s (usually), an Ovary releases an egg, which is picked up by the Fimbriae of the Fallopian Tube, to travel down, meet any sperm that may be present, and create a pregnancy within the Uterus.

Reproduction

Here’s a very brief explanation of how the Female Genital Organs serve as a Reproductive System.  A baby girl is born with over a million immature eggs (oocytes) in her ovaries.  Most die off on their own in childhood & also adulthood.  When a girl reaches puberty, each month hormones from the brain tell the ovaries to produce one mature egg, a process called Ovulation.  That egg lives about a day after ovulation (when it’s released).

For the next 2 weeks, the Endometrial lining of the Uterus begins to prepare itself for a baby to grow.  If the egg happens to meet a sperm and conceive a zygote (the first 2 cells of a future baby), more hormones will direct the Uterus during pregnancy.  But if after 2 weeks no pregnancy has occurred, the Endometrium sheds this developing lining, in the form of the menstrual period (medical term is “menses”).

Here’s an outline of the Menstrual Cycle when no pregnancy occurs (see also Ovulation & the Brain):

Day #1Menstrual Period begins.  At the same time, hormones tell another follicle to begin producing a mature egg for the upcoming month.

Day #14-16 (commonly; though could be any time between Day #7 and #21): Ovulation, when the mature egg is released from an ovary.

Day #28-30 (or more exactly, 14 days after Ovulation):  Next Menstrual Period begins

Note that it doesn’t matter how many days a woman’s period lasts; all that counts is when it begins. So normal cycles may occur every 3 to 5 weeks.

Contraception

A very brief explanation of how various birth control methods work:

  • Barriers (condoms, diaphragms, caps): Prevent sperm from entering the uterus
  • Spermicides: Placed in the vagina to kill sperm there
  • Hormones (pills, injected, implanted):  Interfere with ovulation, so no egg matures
  • IUD:  Placed in the uterus, interfere with movement & function of the sperm and/or egg, in many different ways.  Prevents sperm & egg from successfully creating a baby.
  • Surgery:  Cutting of Fallopian Tubes in women (“tubal ligation”), or the Vas Deferens in men (“vasectomy”), to prevent any passage of egg and sperm, respectively.  Irreversible; even though sometimes the surgery can be undone, never count on it.
  • Rhythm (“Natural Family Planning”):  Not having sex from 5 days before to 2 days after ovulation (sperm can live for 5 days).  The problem is in determining when ovulation occurs, since you can’t count forward from the previous period if the woman is ever irregular.  Taking early morning temperature with a special thermometer, and feeling mucus in the vagina, can also help determine, but a woman needs to be taught well.

Diseases Affecting the Female Genital Tract

Sexually transmitted infections can affect various parts of the genital tract:

Non-Sexual infections also occur:

Conditions that are not infections include:

Cancer can occur in the:

  • Vagina (very rare)
  • Cervix (preventable, or caught early, by Pap tests)
  • Endometrium (mostly after menopause)
  • Ovary

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