ANATOMY/PHYSIOLOGY
The
sexual organs of both men and women are centered in and
around the pelvis (it's like a large bony "bowl" which includes
the hip bones).
FEMALE
SEXUAL ANATOMY
A
woman's outer genital area is called the vulva. The vulva
includes the mons (the area over the pubic bone which is
covered by pubic hair), the labia majora ("outer lips"),
labia minora ("inner lips"), the clitoris, the openings
of the urethra and vagina, and the perineum (area between
the vagina and the anus). A woman's inner reproductive
organs include the two ovaries, the two fallopian tubes,
the uterus, and the vagina. The ovaries are almond-sized
organs and are located one on either side of the uterus.
Between the two ovaries, one mature egg is released during
each normal menstrual cycle. The ovaries also produce hormones,
including estrogen and progesterone.
The
Fallopian tubes are two delicate muscular tubes which are
attached to the upper corners of the uterus, one on either
side. They end in little "fingers" which encircle their
respective ovary. When an egg is released from the ovary,
the "fingers" catch the egg and propel it up the tube towards
the uterus. Fertilization usually occurs in the fallopian
tube, and the fertilized egg takes about three days to travel
to the uterus and implant itself in the uterine lining.
The
uterus is a small muscular organ roughly the size and shape
of an upside-down pear. It has an inner cavity whose lining,
called the ENDOMETRIUM, is rich in blood vessels. This lining
builds up, matures, and sheds over the course of a woman's
monthly menstrual cycle. The biological purpose of the lining
is to serve as rich "soil" for a fertilized egg to "plant"
itself in. If no such egg "plants" itself, the lining is
shed during the woman's "period". If a fertilized egg has
planted itself, the lining is not shed at the end of the
cycle, and the woman "misses her period". A pregnancy has
happened.
The
bottom of the uterus, also called the "neck" or the "cervix",
is the opening to the uterus which protrudes into the vagina.
The vagina, or the "birth canal" is a muscular tube which
is about 4-5 inches long which extends from the opening
of the uterus to the outside world. One end opens to the
outside just below the urethral opening (where urine exits
the body). To learn in more detail about the
female reproductive organs, please visit the Female
Breast & Genital
Guide.
In
order for conception to happen, the egg must be fertilized
by a sperm. In order for the conception to become a normal
pregnancy, the fertilized egg must successfully implant
itself in the lining of the woman's uterus. Preventing one
or the other of these two events forms the basis of all
contraceptive techniques.
MALE
SEXUAL ANATOMY
The
most obvious genital structure in men is the penis. The
penis contains erectile tissue which fills with blood and
becomes stiff and erect when a man is sexually aroused.
The scrotum is the pouch of skin which hangs beneath the
penis. This pouch contains two testicles. Each testicle
produces sperm and the hormone testosterone. During ejaculation,
sperm and substances secreted by other glands mix to form
semen, which is propelled through the urethra and out of
the penis. On average the average ejaculation contains 200
million sperm. The force of the stream of semen and the
numbers of sperm help the chances of a sperm to travel into
the cervix and upwards into the uterus and fallopian tubes,
where it will penetrate and fertilize the waiting egg.
To learn in more detail about the male reproductive organs,
please visit the Male
Genitalia Online Guide.
An
egg is viable (able to be fertilized) for 24-72 hours after
it is released by the ovary. A sperm is viable for about
24 hours after ejaculation. Therefore the time window for
fertilization is quite wide.
