science 10

1. PARTS OF MALE REPRODUCTIVE SYSTEM
• Scrotum
• The scrotum consists of skin. In cold temperatures, the scrotum becomes
firm and wrinkled, reducing the overall size of the scrotum.
• Testes
• The testes are organs within the scrotum each about 4-5 cm long and are
composed of cone-shaped lobules that contain seminiferous tubules, in
which sperm cells develop.
• Epididymis
• Epididymis is a tightly coiled series of thread-like tubules that form a
commashaped structure on the posterior side of the testes. The sperm cells
continue to mature along this tube.

2. Vas deferens
From the epididymis, the sperm moves to this tube up to the ampulla of the ductus deferens. The wall of this tube is
composed of smooth muscles. The vas deferens emerges from the epididymis and ascends along the posterior side of the
testes to become associated with the blood vessels and nerves that supply the testes.
Ejaculatory Duct
The ejaculatory duct connects into the prostate gland and ends by joining the urethra within the prostate gland.
Urethra
The urethra is a pathway for both urine and male reproductive fluids but these do not exit the urethra at the same time. Thus,
there is no mixing. The male urethra connects from the urinary bladder to the distal end of the penis. While seminal fluid
passes through the urethra, a reflex causes the urinary sphincter muscles to contract tightly to keep urine from passing the
urinary bladder through the urethra.
Penis
The penis is only an accessory organ for reproduction and not the reproductive organ itself as most people think of. It is the
organ for copulation and it functions in the transfer of sperm cells from the male to the vagina of the female. It is composed of
erectile tissues and the engorgement of the erectile tissue with blood causes the penis to enlarge and become firm in a
process called erection.

3. The Formation of Sperm Cells
• Each contains two to three highly coiled tubes, the seminiferous
tubules, and this is where sperms develop. Although a testis is only
about 5 cm long, 125 meters of tubes are packed in it. When sperm
cells move out of the testis, they enter a long, coiled duct, the
epididymis. They are not fully developed at this time, but secretions
from the duct walls help them mature. When they are about to leave
the body, they pass through a thick-walled tube called the vas
deferens, and then to the ejaculatory ducts, and finally, to the urethra
where they are ejected. When a male is sexually aroused, sperm cells
begin their journey through the vas deferens and then exit through
the urethra. During this time, they collect fluid along the way.

4. The following glands contribute fluid to the traveling sperm cells:
a) the seminal vesicles secrete a thick fluid that contains nutrients,
B. the prostate gland secretes a thick, milky alkaline fluid to counteract the acidic vagina and the urethra and it activates the
sperms,
C. the bulbourethral gland or Cowper’s gland produces the lubricating effect. Altogether the sperm and the fluids make up the
semen.
 During a male’s arousal, spongy, erectile tissues in the penis are filled with blood, causing the penis to become hard, erect
and enlarged. The semen is expelled during ejaculation passing through the urethral opening when sexual arousal reaches
its peak.
 As previously mentioned, the urethra is a common passageway for urine and semen. However, the nervous system prevents
urine from mixing with the 6 semen during ejaculation. Finally, the penis is an external sex organ that allows the transfer of
the semen into the vagina of the female.

6. Testosterone: The Male Sex Hormone
 Testosterone is the main male sex hormone secreted by the testis. This hormone is responsible for the normal development
of the organs of the male reproductive system. It also brings about the changes experienced during puberty.
 The changes that appear at 10 to 14 years of age eventually distinguish the male secondary characteristics. Secondary male
characteristics among males include growth of facial, underarm, chest, pubic and body hair, enlargement of the voice box,
deepening of the voice, development of the male musculature and increased secretion of sweat and oil. Moreover,
testosterone is responsible for a male’s muscular strength. This is why some athletes take steroids that contain testosterone
or other similar compounds. However, taking steroids have been proven to produce harmful effects and it may even result to
mental problems.

7. Direction: Decide whether the description of each part of the male reproductive system is true or not. Choose A if the statement
is true; otherwise choose B if it is not. A. True B. False
1. In cold temperatures, the scrotum becomes firm and wrinkled, thus reducing the overall size of the scrotum.
2. The penis is composed of epithelial tissues and the engorgement of the erectile tissue with blood causes the penis to enlarge
and become firm.
3. The vas deferens emerges from the epididymis and ascends along the posterior side of the testes to become associated with
the blood vessels and nerves that supply the testes.
4. Testosterone brings about the changes experienced during puberty in males.
5. The ejaculatory duct extends into the prostate gland and ends by joining the urethra within the prostate gland.
6. The penis is only an accessory organ for reproduction and not the reproductive organ itself.
7. The urethra is a pathway for both urine and male reproductive fluids.
8. A man’s testes produce sperm cells which are ejected through ducts during ejaculation.
9. Each testis contains two to three highly coiled tubes, the seminiferous tubules, and this is where sperms develop.
10. The sperm cells continue to mature along the epididymis.