Download Human Reproduction and Development

Human Reproduction and
Development
The Male and Female
Reproductive Systems
The Male Reproductive
System – External Structures
EXTERNAL ORGANS
- The external organs produce, store, and
release the sperm.
VOCABULARY
1. Penis – Contains 3 cylinders of spongy,
erectile tissue that fill with blood during sexual
arousal, causing an erection. The glans is the
highly sensitive tip of the penis.
2. Scrotum – Inside are 2 testicles. Maintains
testes at a temperature of about 5 degrees F
BELOW core body temperature (93F). This is
the best temperature for sperm production.
Male Reproductive System - Diagrams
Internal Organs
- The internal organs are a series of glands and
ducts that store, nourish, and transport the
sperm cells once they are produced.
VOCABULARY
3. Testicles (testes) – Produce sperm and
manufacture the male hormone, testosterone.
Testosterone is mainly responsible for
development of the male secondary sexual
characteristics such as facial and body hair,
deepening voice, and broadening of
shoulders.
More internal structures…
4. Epididymis – Once fully formed, the sperm
produced by the testes move into a tightly
coiled tube called the epididymis that curves
over the top of each testicle. Sperm mature
here while they are stored.
5. Vas deferens – From each epididymis, the
sperm travel into a tube called the vas
deferens. This tube carries sperm up into the
body prior to ejaculation.
6. Seminal Vesicles – a pair of glands that
produce a seminal fluid used to provide
nutrients to the sperm and increase their
mobility.
7. Prostate gland – The 2 vas deferens empty
into a single tube that passes through a
chestnut-shaped structure called the prostate
gland. The fluid contributed from the prostate
increases mobility and helps protect sperm
against the acidic environment of the vagina.
8. Cowper’s glands – These 2 glands secrete
preejaculatory fluid that lubricates the urethra
and neutralized any acid that may remain in
the urethra after urination.
IT IS POSSIBLE FOR A PREGNANCY TO
OCCUR FROM PREEJACULATORY FLUID!
9. Urethra – Tube that starts at the
bladder and runs through the penis to
its end. It carries urine and semen out
of the body, but these substances do
not mix because of the sphincter, which
is a valve that closes off the bladder
during an erection.
Possible Problems with the Male
Sexual Organs
1. Cryptorchidism (undescended testicles)During fetal development, the testes develop
in the abdominal cavity of the male fetus. In
2%-4% of male births, 1 or both testes fail to
descend.
TREATMENT: In most cases, the testicles
descend by themselves before puberty.
Others are treated with surgery and/or
hormones before the age of 5.
2. Phimosis – In this condition, the foreskin is so
tight that it cannot be pulled back to expose
the glans. Diagnosis usually occurs at
puberty; extremely painful erection.
TREATMENT: Circumcision (cutting of foreskin)
More possibilities…
3. Testicular Torsion – rare condition that occurs
when the testicle twists our of normal position,
causing a kink in the vas deferens. Extremely
painful.
TREATMENT: Untwisting of the testicle (needs to
be immediate).
4. Epididymititis – inflammation of the epididymis,
most often caused by the STI chlamydia.
TREATMENT: Antibiotics
5. Testicular Cancer – Most common type of
cancer in men aged 29-35. Curable if treated
early.
TREATMENT: Depends on how far along cancer
is. Medication, removal of tumor, removal of
testicle, or combination.