Page 89 - 86 human physiology part-2

Chapter 16

During sexual excitement, the clitoris erects and extends, the hood retracts, making the clitoral
glans more accessible. The size of the clitoris is variable between women. On some, the clitoral glans is
very small; on others, it is large and the hood does not completely cover it.

Urethra

The opening to the urethra is just below the clitoris. Although it is not related to sex or
reproduction, it is included in the vulva. The urethra is actually used for the passage of urine. The
urethra is connected to the bladder. In females the urethra is 1.5 inches long, compared to males whose
urethra is 8 inches long. Because the urethra is so close to the anus, women should always wipe
themselves from front to back to avoid infecting the vagina and urethra with bacteria. This location
issue is the reason for bladder infections being more common among females.

Hymen

The hymen is a thin fold of mucous membrane that separates the lumen of the vagina from the
urethral sinus. Sometimes it may partially cover the vaginal orifice. The hymen is usually perforated
during later fetal development.

Because of the belief that first vaginal penetration would usually tear this membrane and cause
bleeding, its "intactness" has been considered a guarantor of virginity. However, the hymen is a poor
indicator of whether a woman has actually engaged in sexual intercourse because a normal hymen does
not completely block the vaginal opening. The normal hymen is never actually "intact" since there is
always an opening in it. Furthermore, there is not always bleeding at first vaginal penetration. The
blood that is sometimes, but not always, observed after first penetration can be due to tearing of the
hymen, but it can also be from injury to nearby tissues.

A tear to the hymen, medically referred to as a "transection," can be seen in a small percentage of
women or girls after first penetration. A transection is caused by penetrating trauma. Masturbation and
tampon insertion can, but generally are not forceful enough to cause penetrating trauma to the hymen.
Therefore, the appearance of the hymen is not a reliable indicator of virginity or chastity.

Perineum

The perineum is the short stretch of skin starting at the bottom of the vulva and extending to the
anus. It is a diamond shaped area between the symphysis pubis and the coccyx. This area forms the
floor of the pelvis and contains the external sex organs and the anal opening. It can be further divided
into the urogenital triangle in front and the anal triangle in back.

The perineum in some women may tear during the birth of an infant and this is apparently natural.
Some physicians however, may cut the perineum preemptively on the grounds that the "tearing" may
be more harmful than a precise cut by a scalpel. If a physician decides the cut is necessary, they will
perform it. The cut is called an episiotomy.

304 | Human Physiology