The
Prostate and Accessory Organ
The
prostate gland normally about the size of a chestnut, consists of
a muscular and a glandular portion. The prostate is located
directly below the bladder and surrounds the urethra ( the tube through
which urine passes) as it exits from the bladder. The
relationship of the prostate to the urethra is like a large bead
( the prostate) ona string ( the urethra. Because the rectum (
the lowest part of the bowels) is directly behind the prostate,
the prostate can be examined by a physicians during a rectal
examination. This is important because the prostate can become
infected or cancerous.
The
prostate produces clear fluid that makes up about 30 % of
seminal fluid, the liquid that is expelled from the penis during
ejaculation. The other 70% of seminal fluid comes from the
seminal vesicles. These two small structure s lie against the
back portion of the base of the of the bladder and join with the
ends of the vas deferens to form the ejaculatory ducts. These
ducts in turn join the urethra, thereby creating a continuous
tubing system that leads to the end of the penis.
On
the average, there are 3 to 5 milliliters ( 5 ml = about 1
teaspoonful) of semen ( seminal fluid plus sperm) per ejaculate.
Although the concentration of sperm is highly variable,
depending in part on the frequency of ejaculation, a count of 40
to 120 million per ml is considered normal. This means that
there may be 120 to 600 million sperm in a single ejaculate.
Seminal
fluid ranges in color from whitish to tones of yellow or gray
and has a creamy, sticky texture. Right after ejaculation,
seminal fluid is rather thick but then it liquefies quickly. It
consists of water, mucus , and a large number of chemical
substances that include sugar ( providing a energy source for
sperm), bases for neutralizing the acidity of the male urethra
and the female vagina) , and prostateglandins ( hormones that
cause contractions in the uterus and Fallopian tubes, possibly
aiding upward transit of sperm).
Cowper's
gland are two pea - sized structures connected to the urethra
just below the prostate gland. They produce a few drops of
fluid, which sometimes appear at the tip of the penis during
sexual arousal but before ejaculation. Some men never notice
this pre-ejaculatory fluid, while others may produce a
teaspoonful or more of this slippery secretion. Although this
pre-ejaculatory fluid may buffer the acidity of the urethra,
there no certainity about its function. Occasionally, the
pre-ejaculatory fluid contains a small number of live sperm
cells , accounting for at least some of the "failures"
as a method of birth control of withdrawal of penis before
ejaculation.
The
Breasts
The
male breasts have nipples and areolas but have little under
lying glandular tissue or fatty padding. The male nipple and
areola seem to be less sensitive to touch and pressure than
the same structures in adult females. Nevertheless, some
males find that having their breasts or nipples stroked or
licked is sexually arousing. Others do not notice any erotic
pleasure from such practices.
Sometimes
one or both of a male's breasts may become enlarged. This
condition, called gyneconastia, occurs in 40 to 60 percent of
boys during puberty but usually disappears within a year or two.
In adulthood, it may be caused by alcoholism, liver
disease, thyroid disease, Drug ingestion, or certain
forms of cancer. When gynecomastia is so severe that
it creates major psychological problems, it can be
corrected by relatively simple surgery.
The
male breasts can also become enlarged if a man takes estrogen
over a period of time . As we will discuss in chapter 8 most
male -to-female transsexuals undergo such treatment. we have
also seen a case in which a man unwittingly took birth control
pills for several months, causing the same result.
