Male Reproductive
System
External/Internal
Function
 What is the main function of the male reproductive
system?
 When do males begin producing sperm?
 What gland secretes a hormone that causes testes to
begin producing testosterone?
Function
 Male reproductive system functions to produce sperm-the
male reproductive cell
 A sperm cell unites with a female egg cell (ovum) to form a
fertilized ovum.
 Males do not begin producing sperm until puberty
 The pituitary gland secretes a hormone that causes the
testes to begin producing sperm
 Once a male reaches puberty and begins producing sperm,
he is capable of producing sperm for the rest of his life.
(Spermatogenesis)
External Male Reproductive
Organs
 External male reproductive organs include the
scrotum,testes,and penis.
 Testes-male sex glands-serve 2 functions
 Manufacture the male sex hormone-testosterone
 Produce male reproductive cells-sperm
 Scrotum-sac that hangs outside the body that holds the
testes
 Penis- tube like organ that functions in sexual
reproduction, sexual pleasure, and elimination of body
wastes.
Scrotum
 Loose pouch of skin that becomes darker as males grow
and develop.
 As puberty progresses, hair will appear
 As testes grow skin of scrotum becomes wrinkled.
 Main function is to keep testes at the right temperature so
they can produce sperm (3-4 degrees lower then normal
body temp of 98.6)
 If body temp rises, muscles in scrotum relax to lower the
testes away from the body. If body temp lowers, muscles of
scrotum contract to pull the testes close to the body.
Testes
 Sperm is actually produced in a section of the testes
called seminiferous tubules.
 Seminiferous tubules-long series of threadlike tubes
packed in testes. (about 1000 each about 1-3 ft long-combined length of all tubules
can extend almost ½ mile capable of producing billions and billions of sperm.)
 The testes produce 500million or more sperm each day
 Once sperm are produced they move to epididymis.
Epididymis
 *Highly coiled structure located on the backside of
each of the testes.
 Stores newly produced sperm
 20 ft in length.
 The maturation of sperm which began in the
seminiferous tubules, continues to the epididymis
 It takes about 72 days from the time sperm are
produced until they become fully mature.
Sperm Cell
 Very tiny- consists of head,neck,middle piece and tail
 Carries 23 chromosomes in the head-1/2 the number of
chromosomes in all other cells of body
 When sperm unites with ovum,which carries 23
chromosomes-the results is one cell of 46 chromosomes
and the production of a human offspring
Penis
 Tubelike organ that functions in sexual reproduction, sexual
pleasure and elimination of body wastes.
 Made up of three long cylinders of spongy tissue
 Tissue is filled w/spaces much like a sponge that contain a very
rick supply of blood vessels and nerves
 When penis is soft these cylinders contain little blood
 When blood from circulatory system fills these spaces the penis
becomes enlarged and hard-erection
 Contrary to what some people think, the penis is neither a muscle
nor a bone.
 Erections result entirely from blood flow.
Erections and Ejaculation
 Erection-increased blood flow to the penis
 Males of all ages experience erections and can occur for no reason at all
 At puberty the penis becomes more sensitive and erections are more
often
 Ejaculation-is a series of muscular contractions releasing semen
 Semen-is thick fluid containing sperm and other fluid
 In less than a teaspoon of semen there are about 300-400 million sperm.
 When males begin to produce sperm nocturnal emission can occur which
is ejaculation during sleep
Circumcision
 All male babies are born with a fold of skin covering end
of penis-foreskin
 Circumcision is the removal of the foreskin
 Some circumcision is performed as a religious custom
 Doctors thought it was necessary for health reasons to
remove, but not necessary.
 In recent years about ½ of parents chose not to.
Internal Male Reproductive
Organs
 Vas Deferens
 Seminal Vesicles
 Prostate Gland
 Cowper’s Gland
 Urethra
Vas Deferens
 Vas Deferens-2 long tubes that connect the epididymis
with the urethra
 Lined w/ cilia(fingerlike projections)which help move
sperm through tube
 Vas deferens loop over pubic bone, around bladder ,
and through prostate gland.
 As it passes through prostate gland it narrows and
becomes the ejaculatory duct into urethra
Seminal Vesicles
 Two little pouches above and on either
side of prostate gland.
 SVs' secrete a fluid that mixes w/sperm
 This fluid helps make sperm mobile and
provides nourishment to the sperm.
Prostate Gland
 Lies just below the bladder and surrounds the urethra
 Made up of both muscular and glandular tissue
 Secretes a milky,alkaline fluid that mixes w/sperm and
makes up major portion of semen.
 It is this solution that helps protect sperm by neutralizing
the acidity of the urethra and vagina in the female
Cowper’s Gland
 Two pea-sized glands below the prostate that open into
urethra
 Secrete clear, sticky fluid that is thought to cleanse urethra
of acid from urine allowing the safe passage of sperm
 Semen-mixture of sperm and fluids from the seminal
vesicles,prostate gland,and Cowper’s Gland
 Some of the clear fluid from the Cowper’s gland is released
before the semen is released-this secretion causes droplets
of fluid to form on the end of penis before ejaculation
 These droplets of fluid can contain sperm-pregnancy can
occur.
Urethra
 Tubelike organ that travels through the penis.
 Serves as a passageway for sperm and urine, however
both can not leave the body at same time.
 Special muscles surround the urethra at the base of the
bladder that contact and close off bladder preventing
urine to be released when semen is leaving body
Concerns About Male Reproductive
System
 Hernia
 Sterility
 Cancer of Testes or Prostate
Hernia
 Pushing of a part of the body through the muscle wall
normally keeping it in (several types)
 Inguinal hernia-common hernia of reproductive system
where part of the intestine can push through abdominal
wall into the scrotum.
 Surgery can correct this and males can help avoid this
by using care when lifting or pushing heavy objects- lift
w/legs not back.
Sterility
 Condition wherein sperm of male is
weak,malformed,sparse or nonexistent, or unable to join
an ovum.
 Fertilization can not take place
 Causes of sterility: temperature changes, exposure to
certain chemicles,smoking,contracting mumps as an
adult,untreated STD,faulty operation of epididymis,vas
deferens,or urethra
Testicular Cancer
 Most common cancer in men ages 15-34 yrs
 If discovered in early stages, testicular cancer can be
treated properly and effectively.
 1st sign-usually slight enlargement of one of the testes and
change in its consistency.
 May be small, hard lump in testicle or a collection of fluid or
blood in scrotum.
 There might be no pain-but often there is a dull ache in
lower abdomen and groin
 Men who have an undescended or partial descended
testicle are at high risk
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Male Reproductive System