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Penis
A penis is the male
sexual and reproductive organ, consisting of a head, called the glans,
and the shaft or body. A fold of skin called the foreskin covers the
glans. The foreskin is like a hood and can be rolled back to expose the
head of the penis. The body or shaft of the penis is made up of three
cylinders of soft, spongy tissue, which contain many small blood
vessels. The entire penis contains many nerve endings that make it
sensitive to touch, pressure, and temperature. The glans, however, has a
higher concentration of nerve endings than the shaft of the penis and is
thus particularly sensitive to physical stimulation. Two other areas
that are highly sensitive are the rim that separates the glans from the
shaft of the penis, called the coronal ridge, and the small triangular
region on the underside of the penis where a thin strip of skin called
the frenulum attaches to the glans. During sexual excitement, the blood
vessels of the spongy tissue fill with blood and swell up. The rapid,
forceful dilation of these blood vessels throughout the entire penis
causes it to become firm and grow in size. This transition from a soft
(flaccid) penis to a harder, stiffer penis is called getting an
erection. The penis usually returns to a softer (non-flaccid) state
shortly after ejaculation or after the penis is no longer being
stimulated. The erect penis is inserted into a woman's vagina during the
sexual act called intercourse
or coitus. When a man reaches the pinnacle of sexual excitement, his
orgasm is often accompanied by spurts of semen from the opening at the
tip of the glans. This is called ejaculation.
The semen that is released from the penis during ejaculation contains
sperm, the reproductive cell capable of fertilizing an ovum or egg, the
female reproductive cell. When one of the millions of sperm encounters
an egg inside a woman's body, their union can produce a pregnancy. The
appearance of the penis varies considerably from one male to another.
There can be differences in color, shape, size, and the status of the
foreskin (circumcised or uncircumcised). A man's weight, build and
height bear no relation to the size of his penis in either the soft or
erect state, nor is penis size related to his foot, hand or nose size.
Art and the media, particularly men's magazine's and erotic books and
movies, often portray male genitals in "larger than life"
dimensions, giving men an unrealistic standard of comparison that can
contribute to their concerns about their penis size. Concerns about
penis size are common among men of all ages. When a penis is soft it
usually hangs loosely away from the body and averages about 3.5 to 4.5
inches in length and one inch in diameter, though some are smaller and
some are larger. The same penis can vary in size even when soft. For
instance, cold air, cold water, fear, anger or anxiety causes the penis,
scrotum and testicles to be pulled closer to the body, thereby
shortening it. By the same token, a soft penis can actually lengthen in
warm conditions and when a man is completely relaxed. Although the size
of the non-erect penis differs widely from one male to another, this
variation is less apparent in the erect state. Masters, Johnson and
Kolodny (1986) in their book Sex and Human Loving state that
erection can be thought of as "the great equalizer" because
men with a smaller non-erect penis usually have a larger percentage
volume increase during erection than men who have a larger flaccid
penis. The great interest in penis size is related to several different
things. First, it shows a concern for being "normal" - the
same as everyone else, or certainly no worse. Second, it is related to a
wish to be sexually adequate. Many people in our society believe that
"bigger is better" and the myth that a big penis will provide
more sexual satisfaction to a woman is widespread. Actually, penile
diameter has little physiological effect for the woman because the
vagina can gradually adjust to fit a penis of any circumference
(remember, it is designed, under the right conditions, to allow a baby
to pass through the same opening). The length of the penis, which
determines the depth of vaginal penetration, is relatively unimportant,
because it is the first one-third of the vagina that has the most nerve
endings and is most responsive to physical stimulation. Penis size may,
however, have positive or negative psychological significance to a
woman. Some women prefer a large penis; others are put off by what they
think is "too large" or "too small". Third, men may
feel that a larger penis gives them an element of status and makes them
more sexually attractive.
Sometimes, shortly after
birth, the foreskin is removed from the penis in a procedure known as
circumcision.
The decision to perform a circumcision is often made for religious
reasons, and in some rare cases it is necessary in order to release a
foreskin that is too tight around the penis. Many physicians and parents
also feel removal of the foreskin promotes better hygiene, although with
little evidence to support this claim, some now choose to forego
circumcision of infant boys.
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Sex
