Male Reproduction
(Illustrations are in your health book p. 328-329)
Male Reproductive Organs
Most of the male reproductive organs are located on the outside of the body.
Genitals are organs located outside of the body. The penis and scrotum are the male
genitals that are located outside the body. The scrotum is a pouch behind the penis and
contains the testes. The penis grows during puberty, like other organs do. The size is
different from person to person, but the size is not important to its function.
The head of the penis is called the glans. This fold of skin is called foreskin.
Sometimes the parents ask the doctor to perform a circumcision, which surgically
removes the foreskin shortly after birth. Males who are not circumcised must be careful
to pull back the foreskin when they bathe, because bacteria can grow in there and cause
an infection.
Testicles, or testes, are responsible for making sperm, which is the male sex cell.
Some testicles might not be the same and size and one may hang lower than the other, but
this is not a reason for concern. Testicles sometimes appear to change in size because of
the movement of a layer of muscles below the skin in the scrotum. When cold air or
water is exposed to the scrotum, the muscles draw the testicles close to the body. In
warm air the scrotum hangs loosely because warmth relaxes the muscles in the scrotum.
This keeps the level of sperm development high because you body controls its
temperature.
Functions of the Male Reproductive Organs
Spongy tissue and blood vessels are what make up the inside of the penis. The
glans, or tip of penis is the most sensitive part with many nerve endings. Most of the
time, a male’s penis is soft and limp. When a penis is stimulated, blood fills the spongy
tissues. This is called an erection, where the penis stiffens and extends away from the
body.
Nocturnal ejaculation, or wet dream, occurs when semen is released during a
male’s night sleep. A teaspoon of sticky, milk-colored fluid passes onto bedclothes or
sheets. There is no need to panic about the situation, wet dreams are common and
uncontrollable and may occur many times during his life, or not at all. All of these
experiences are normal.
The reproductive organs of a male are very sensitive and need to be protected
from injury. Protective cups or straps, such as athletic supporter, should be worn during
vigorous activity. When playing contact sports, such as, football, baseball, basketball,
hockey, or soccer males should always protect their testes and penis from injury.
Male Sex Cells
When a male reaches puberty the testicles begin to make sperm. The testes
contain a great number of coiled tubes. These tubes are where the sex cells, or the sperm,
are made. Each tube runs one to three feet long, and it takes 60 days for a sperm to form
in a testicle. The average male produces about 300 million sperm each day. As the
sperm mature they travel through the male reproductive system. Sperm production
begins at puberty and goes on throughout a male’s lifetime. The sperm travel through
small tubes from the testicles to the epididymis, which is located above and behind each
testicle. After the sperm have been in the epididymis for a period of 18 hours to 10 days,
they become mature enough to fertilize an egg. They have a round like head, a thick
middle part and a long tail. The genetic traits are located in the round head.
A long tube called the vas deferens is where the sperm enters after it leaves the
epididymis. All of these tubes lead up into the body and over the bladder. The sperm is
stored mostly in the widest part of the vas deferens for as little as a few hours up to
several months. Under each widened section of the vas deferens is tiny gland known the
as the seminal vesicles. When sperm move from the vas deferens, they enter a single
tube that runs through the prostate gland. The seminal vesicles release a fluid giving the
sperm nutrients and offers protection for the sperm.
The fluid from the seminal vesicles and the sperm now enter a tube that runs
through the prostate gland, which also gives off a fluid. The mixture of fluids and sperm
in the tube is called semen.
Semen moves through the prostate gland into a tube called the urethra. The
urethra runs through the penis. Semen and urine run through the urethra, but not at the
same time. The bladder is where the urine is stored before it is released into the urethra.
When semen enters the urethra a muscle closes off the connection between the urethra
and bladder. Once sperm is ejaculated inside the female reproductive system, a sperm
uses its tail to move toward the ripened egg.
Answer the following questions on a separate sheet of paper.
Define the following terms
1. semen
2. scrotum
3. urethra
4. genitals
5. vas deferens
6. circumcision
Answer the following questions in complete sentences.
7. When do males produce sperm?
8. How do muscles in the scrotum affect the appearance of the testes?
9. Explain the role of blood in an erection?
10. What role do seminal vesicles play in production?