THE REPRODUCTIVE SYSTEM
4th partial
8th grade
The Male Reproductive System
The organs of the male reproductive system
are specialized for the following functions:
• To produce, maintain and transport sperm
(the male reproductive cells) and
protective fluid (semen)
• To discharge sperm into the female
reproductive tract
• To produce and secrete male sex hormones
The human male reproductive system (or
male genital system) consists of a number
of sex organs that are a part of the human
reproductive process. These sex organs are
located outside the body.
The main male sex organs are:
• the penis and the testes which produce
semen and sperm.
When there is sexual intercourse it fertilizes an
ovum in the female body and the fertilized
ovum (zygote) gradually develops into a fetus,
which is later born as a child.
• The male reproductive anatomy includes
internal and external structures.
• What are the external reproductive structures?
Most of the male reproductive system is located outside of
the man’s body : the penis, the scrotum and the testicles.
• Penis — is the male organ for sexual
intercourse. It has three parts:
a.Root attached to the wall
of the abdomen
• b.Body, or shaft
• c.Glans, called the head of the
Penis covered with a loose layer of skin
called foreskin. (This skin is sometimes
removed in a procedure called
circumcision.)
The opening of the urethra, the tube that transports semen and
urine, is at the tip of the glans penis. The penis also contains a
number of sensitive nerve endings.
• The body of the penis is cylindrical in shape and consists of
three internal chambers. These chambers are made up of
special, sponge-like erectile tissue. This tissue contains
thousands of large spaces that fill with blood when the man is
sexually aroused. As the penis fills with blood, it becomes
rigid and erect, which allows for penetration during sexual
intercourse. The skin of the penis is loose and elastic to
accommodate changes in penis size during an erection.
• Testicles (testes) — The testes are oval organs about the size
of large olives that lie in the scrotum, secured at either end by
a structure called the spermatic cord. Most men have two
testes.
• The testes are responsible for making s, the primary male sex
hormone, and for generating sperm. Within the testes are
coiled masses of tubes called seminiferous tubules. These
tubules are responsible for producing the sperm cells through
a process called spermatogenesis.
• Epididymis — The epididymis is a long, coiled tube
that rests on the backside of each testicle. It
functions in the transport and storage of the sperm
cells that are produced in the testes. It also is the
job of the epididymis to bring the sperm to
maturity, since the sperm that emerge from the
testes are immature and incapable of fertilization.
During sexual arousal, contractions force the sperm
into the vas deferens.
Vas deferens and Ejaculatory Ducts
• Vas deferens — The vas deferens is a long, muscular tube that
travels from the epididymis into the pelvic cavity, to just
behind the bladder. The vas deferens transports mature
sperm to the urethra in preparation for ejaculation.
• Ejaculatory ducts — These are formed by the fusion of the
vas deferens and the seminal vesicles. The ejaculatory ducts
empty into the urethra.
•
The urethra is the tube that carries urine from the bladder to
outside of the body. In males, it has the additional function of
expelling (ejaculating) semen when the man reaches orgasm.
When the penis is erect during sex, the flow of urine is
blocked from the urethra.
• Seminal vesicles are sac-like pouches that attach to the vas
deferens near the base of the bladder. The seminal vesicles
produce a sugar-rich fluid (fructose) that provides sperm with
a source of energy and helps with the sperms’ motility (ability
to move).
• Prostate gland — The prostate gland is
a walnut-sized structure that is located
below the urinary bladder in front of
the rectum. The prostate gland
contributes additional fluid to the
ejaculate. Prostate fluids also help to
nourish the sperm.
• How does the male reproductive system
function?
The entire male reproductive system is
dependent on hormones, which are chemicals
that stimulate or regulate the activity of cells
or organs. The primary hormones involved in
the functioning of the male reproductive
system are follicle-stimulating hormone (FSH),
luteinizing hormone (LH) and testosterone.
The human female reproductive system (or female genital system)
Contains two main parts: the uterus,
which hosts the developing fetus, produces
vaginal and uterine secretions, and
the ovaries, which produce the
egg cells. These parts are internal.
The vagina meets the external organs at the vulva,
which includes the labia, clitoris and
urethra.
The vagina is attached to the
uterus through the cervix, while the uterus
is attached to the ovaries via the Fallopian
tubes. At certain intervals, the ovaries release
an ovum, which passes through the Fallopian tube
into the uterus.
• If, in this transit, it meets with sperm, the
sperm penetrate and merge with the egg,
fertilizing it. The fertilization usually occurs in
the oviducts, but can happen in the uterus
itself. The zygote then implants itself in the
wall of the uterus.
• When developed enough to survive outside
the womb, the cervix dilates and contractions
of the uterus propel the fetus through the
birth canal, which is the vagina.
• Uterus
• The uterus or womb is the major female
reproductive organ of humans. The uterus
provides mechanical protection, nutritional
support, and waste removal for the
developing embryo (weeks 1 to 8) and fetus
(from week 9 until the delivery). In addition,
contractions in the muscular wall of the uterus
are important in pushing out the fetus at the
time of birth.
• The fertilized ovum becomes an embryo,
develops into a fetus and gestates until
childbirth. If the egg does not embed in the
wall of the uterus, an anatomically female
person begins menstruation and the egg is
flushed away.
• Oviducts
• The Fallopian tubes or oviducts are two tubes
leading from the ovaries into the uterus.
• On maturity of an ovum, the follicle and the
ovary’s wall rupture, allowing the ovum to
escape and enter the Fallopian Tubes. There it
travels toward the uterus. This trip takes hours
or days. If the ovum is fertilized while in the
Fallopian tubes, then it normally implants in
the uterus, which signals the beginning of
pregnancy.
• Ovaries
• The ovaries are small, paired organs that are
located near the lateral walls of the pelvic
cavity. These organs are responsible for the
production of the ova and the secretion of
hormones. Ovaries are ova or eggs are
produced. The process by which the ovum is
released is called ovulation.
• After ovulation, the ovum is captured by the
oviduct, after traveling down the oviduct to
the uterus, occasionally being fertilized on its
way by an incoming sperm, leading to
pregnancy and the eventual birth of a new
human being.
• In the absence of fertilization, the ovum will
eventually traverse the entire reproductive
tract from the fallopian tube until exiting the
vagina through menstruation.
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Explain the two functions of the urethra.
What are the hormones involved in the male reproductive system?
What male characteristics does testoterone develop?
What is the male foreskin?
What is the ovum?
What is a zygote?
What happens when the ovum comes through the Fallopian tubes
and meets with sperm at the uterus’
• What happens when the ovum comes through the fallopian tubes
and does not meet with sperm?
• What does uterus provide to the embryo?
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Define the following.
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penis
uterus
ovums
testoterone
glans
urethra
testes
womb
epidydimis
scrotum
foreskin
What is the function of Vas Deferens?
What is the function of Seminal Vesicles?
What is the function of epididymis?