Download The Testicles

The Testicles
The Greatest Organ Known to Man
Function
The testicles have two primary functions:
1. The production of testosterone
2. Production of sperm cells
The testes secrete hormones such as
testosterone and that is why they are an
endocrinal gland
Testosterone
• Testosterone secretion is regulated by a negative feedback system that
involves releasing hormones from the hypothalamus and
gonadotropins from the pituitary.
• Testosterone is the male sex hormone. Testosterone will cause a boy to
change into a man during puberty: he will grow a beard, his voice will
get a lower pitch, his penis will grow, he will be able to have erections
and will develop feelings of lust.
• Testosterone also inhibits LH production by the pituitary by
deactivating the hypothalamus.
Testosterone Feedback System
Sperm Cells
• The mature sperm cell (spermatozoa) is 0.05 millilitres long. It
consists of a head, body and tail. The head is covered by the ac
cap and contains a nucleus of dense genetic material from the
23 chromosomes.
• It is attached from the neck to the body containing mitochondria
that supply the energy for the sperm's activity. The tail is made
of protein fibres that contract on alternative sides, giving a
characteristic wavelike movement that drives the sperm through
the seminal fluid, which also supplies additional energy.
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Sperm swim at an average rate of about 3mm (0.12 inches) per minute.
Sperm cells are made in the testes where it takes about 72 days for
one sperm to grow.
Sperm Cells Continued
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Healthy Males make 200-300 million sperm cells every day.
Semen contains small amounts of more than thirty elements, including
fructose, ascorbic acid, cholesterol, creatine, citric acid, lactic acid,
nitrogen, vitamin B12, and various salts and enzymes.
All normal cells have 46 chromosomes but sperm have half that
number or, 23. If and when the sperm joins ups with the female’s, egg
(ovum) which also has 23 chromosomes, together they add up to 46
chromosomes.
The sperm make up only about 5% of what a man ejaculates each time
he ejaculates and a single sperm is the smallest cell in the body.
Other Functions
• The functions of the testicles are under
control of the anterior pituitary gland which
secretes luteinizing hormone and folliclestimulating hormone. These are known as
gonadotropic hormones.
LH
• The release of luteinizing hormone is
controlled by pulses of gonadotrophinreleasing hormone (GnRH) from the
hypothalamus. It is responsible for the
release of testosterone.
FSH
• FSH regulates the development, growth,
pubertal maturation, and reproductive
processes of the human body. FSH and LH
are partners in an atrospect. Like LH, the
release of FSH is controlled by pulses of
gonadotrophin-releasing hormone (GnRH)
from the hypothalamus. FSH also acts
directly on the sperm producing cells of the
seminiferous tubules.
Anatomy
• The epididymis is
connected to the
testicle and overlies it
like a cap; it contains a
very large amount of
microscopically small
tubes. From the
epididymis, the vas
deferens will conduct
the freshly made sperm
cells to the area of the
prostate.
Anatomy Continued
• The vas deferens runs together with blood vessels
that supply blood to and from the testicle and some
muscle fibers; as a sort of long thin sausage they
perforate the abdominal wall at the groin. Since, from
the standpoint of the abdomen, the testicles are
located 'outside' the body, there must be a tiny hole in
the abdominal wall there to let the vas deferens in.
Right behind the prostate the vas deferens joins the
outlets of the seminal vesicles to be able to leave the
body through the urethra as semen, in search of a
female egg cell.
Did You Know?
• The testicles are round in shape and about
the size of golf balls. The are equivalent to
to ovaries in women and for the first six
weeks of age the gonads (which later
develop into sex organs) are the same for
males and females.
Homeostasis
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One homeostatic mechanism in the testicles is the reaction to temperature.
There are a number of muscles that raise and lower the testes to maintain the
optimum temperature. The main one is the cremasteric muscle. The
cremasteric muscle shortens and pull the testicle closer toward the body, which
provides more warmth when the outside temperature is cool. When testicle
cooling is necessary, the cremasteric muscle relaxes and the testicle is lowered
away from the warm body to cool.
Disorders
• There are many disorders linked with the testicles, primarily STD’s.
An example of one of these STD’s is gonorrhea. Gonorrhea is cause
by a bacteria that can grow and multiply in practically all areas of the
reproductive tract. Gonorrhea is a very common infectious disease.
More than 700, 000 people in the U.S. get new gonorrhea infections
each year.
Chlamydia
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Chlamydia infection is caused by the bacteria bacterium Chlamydia Trachomatis.
Chlamydia infection is one of the most common sexually transmitted infections
worldwide — about 2.8 million cases of chlamydia infection occur in the United States
each year. It is the most common STD in the U.S. with gonorrhea being the second.
Chlamydia is known as a "silent" disease because about three quarters of infected
women and about half of infected men have no symptoms
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Some symptoms can include a burning sensation when urinating or in rare cases pain
and swelling in the testicles.
Chlamydia can lead to such things as infertility and discharge of the penis
Male Reproductive Tract Abnormalities
Did You Know?
• Two common male reproductive tract abnormalities are
cryptorchidism, where the testicles haven’t descended after age
one, and hypospadias, a common abnormality of the penis that
appears as an abnormal opening on the underside of the penis
rather than at the end