short notes on human male reproductive system

1. Human male reproductiveHuman male reproductive
systemsystem

2. Function of male reproductiveFunction of male reproductive
systemsystem
 1-1-to produce,maintain,transport spermsto produce,maintain,transport sperms
and protect seminal fluid.and protect seminal fluid.
2-2-to discharge sperm within the femaleto discharge sperm within the female
reproductive system during sex.reproductive system during sex.
3-3-to produce and secret male sex.to produce and secret male sex.
hormones for maintaining the reproductivehormones for maintaining the reproductive
system.system.

3. Formation of male reproductiveFormation of male reproductive
systemsystem
 Unlike female reproductive system,most ofUnlike female reproductive system,most of
male reproductive system located outsidemale reproductive system located outside
the body.the body.
These external structures include:-These external structures include:-
penis,scrotum and testiclespenis,scrotum and testicles

5.  Penis:-Penis:-male organ used in sexualmale organ used in sexual
intercourse.intercourse.
It composed from three parts:-It composed from three parts:-
1:-1:-root:-root:-which attached to the wall of thewhich attached to the wall of the
abdomen.abdomen.
2:-2:-body or shaft:-body or shaft:-cone shaped part at thecone shaped part at the
end of the penis.end of the penis.
3:-3:-the glands:-the glands:-also called the head of thealso called the head of the
penis which is covered with lose layer ofpenis which is covered with lose layer of
skin called roreskin.skin called roreskin.

6.  1-penis:-1-penis:-The body of the penis is cylindrical in shapeThe body of the penis is cylindrical in shape
and consists of three circular shaped chambers.and consists of three circular shaped chambers.
These chambers are made up of special, sponge-These chambers are made up of special, sponge-
like tissue. This tissue contains thousands of largelike tissue. This tissue contains thousands of large
spaces that fill with spaces that fill with bloodblood when the man is sexually when the man is sexually
aroused. As the penis fills with aroused. As the penis fills with bloodblood, it becomes, it becomes
rigid and erect, which allows for penetration duringrigid and erect, which allows for penetration during
sexual intercourse. The skin of the penis is loosesexual intercourse. The skin of the penis is loose
and elastic to accommodate changes in penis sizeand elastic to accommodate changes in penis size
during an erection.during an erection.
 Semen, which contains sperm (reproductive cells), isSemen, which contains sperm (reproductive cells), is
expelled (ejaculated) through the end of the penisexpelled (ejaculated) through the end of the penis
when the man reaches sexual climax (orgasm).when the man reaches sexual climax (orgasm).
When the penis is erect, the flow of urine is blockedWhen the penis is erect, the flow of urine is blocked
from the urethra, allowing only semen to befrom the urethra, allowing only semen to be
ejaculated at orgasm.ejaculated at orgasm.

7.  Scortum:-Scortum:-This is the loose pouch-like sac ofThis is the loose pouch-like sac of
skin that hangs behind and below the penis.skin that hangs behind and below the penis.
It contains the testicles (also called testes),It contains the testicles (also called testes),
as well as many nerves and blood vessels.as well as many nerves and blood vessels.
The scrotum acts as a "climate controlThe scrotum acts as a "climate control
system" for the testes. For normal spermsystem" for the testes. For normal sperm
development, the testes must be at adevelopment, the testes must be at a
temperature slightly cooler than temperature slightly cooler than
body temperaturebody temperature. Special muscles in the. Special muscles in the
wall of the scrotum allow it to contract andwall of the scrotum allow it to contract and
relax, moving the testicles closer to therelax, moving the testicles closer to the
body for warmth or farther away from thebody for warmth or farther away from the
body to cool the temperature.body to cool the temperature.

8.  Testes:-Testes:- These are oval organs about the These are oval organs about the
size of large olives that lie in the scrotum,size of large olives that lie in the scrotum,
secured at either end by a structure calledsecured at either end by a structure called
the spermatic cord. Most men have twothe spermatic cord. Most men have two
testes. The testes are responsible fortestes. The testes are responsible for
making making testosteronetestosterone, the primary male sex, the primary male sex
hormone, and for generating sperm.hormone, and for generating sperm.
Within the testes are coiled masses ofWithin the testes are coiled masses of
tubes called seminiferous tubules. Thesetubes called seminiferous tubules. These
tubes are responsible for producing spermtubes are responsible for producing sperm
cells.cells.

9.  Epidymis:-Epidymis:-The epididymis is a long, coiledThe epididymis is a long, coiled
tube that rests on the backside of eachtube that rests on the backside of each
testicle. It transports and stores spermtesticle. It transports and stores sperm
cells that are produced in the testes. Itcells that are produced in the testes. It
also is the job of the epididymis to bringalso is the job of the epididymis to bring
the sperm to maturity, since the spermthe sperm to maturity, since the sperm
that emerge from the testes are immaturethat emerge from the testes are immature
and incapable of fertilization. Duringand incapable of fertilization. During
sexual arousal, sexual arousal, contractionscontractions force the force the
sperm into the vas deferens.sperm into the vas deferens.

10.  Vas deferens:-Vas deferens:-The vas deferens is a long,The vas deferens is a long,
muscular tube that travels from themuscular tube that travels from the
epididymis into the pelvic cavity, to justepididymis into the pelvic cavity, to just
behind the behind the bladderbladder. The vas deferens. The vas deferens
transports mature sperm to the urethra,transports mature sperm to the urethra,
the tube that carries urine or sperm tothe tube that carries urine or sperm to
outside of the body, in preparation foroutside of the body, in preparation for
ejaculation.ejaculation.

11.  Ejeculatory ducts:-Ejeculatory ducts:-These are formed byThese are formed by
the fusion of the vas deferens and thethe fusion of the vas deferens and the
seminal vesicles (see below). Theseminal vesicles (see below). The
ejaculatory ducts empty into the urethra.ejaculatory ducts empty into the urethra.

12.  Urethera:-Urethera:-The urethra is the tube thatThe urethra is the tube that
carries urine from the carries urine from the bladderbladder to outside of to outside of
the body. In males, it has the additionalthe body. In males, it has the additional
function of ejaculating semen when the manfunction of ejaculating semen when the man
reaches orgasm. When the penis is erectreaches orgasm. When the penis is erect
during sex, the flow of urine is blocked fromduring sex, the flow of urine is blocked from
the urethra, allowing only semen to bethe urethra, allowing only semen to be
ejaculated at orgasm.ejaculated at orgasm.

13. GlandsGlands
 Prostate gland:-Prostate gland:-The prostate gland is aThe prostate gland is a
walnut-sized structure that is locatedwalnut-sized structure that is located
below the urinary bladder in front of thebelow the urinary bladder in front of the
rectum. The prostate gland contributesrectum. The prostate gland contributes
additional fluid to the ejaculate. Prostateadditional fluid to the ejaculate. Prostate
fluids also help to nourish the sperm. Thefluids also help to nourish the sperm. The
urethra, which carries the ejaculate to beurethra, which carries the ejaculate to be
expelled during orgasm, runs through theexpelled during orgasm, runs through the
center of the prostate gland.center of the prostate gland.

14.  Bulboretheral gland:-Bulboretheral gland:-Also called Cowper'sAlso called Cowper's
glands, these are pea-sized structuresglands, these are pea-sized structures
located on the sides of the urethra justlocated on the sides of the urethra just
below the prostate gland. These glandsbelow the prostate gland. These glands
produce a clear, slippery fluid that emptiesproduce a clear, slippery fluid that empties
directly into the urethra. This fluid serves todirectly into the urethra. This fluid serves to
lubricate the urethra and to neutralize anylubricate the urethra and to neutralize any
acidity that may be present due to residualacidity that may be present due to residual
drops of urine in the urethra.drops of urine in the urethra.

15.  Follicle-stimulating hormone is necessaryFollicle-stimulating hormone is necessary
for sperm production (spermatogenesis),for sperm production (spermatogenesis),
and luteinizing hormone stimulates theand luteinizing hormone stimulates the
production of testosterone, which is alsoproduction of testosterone, which is also
needed to make sperm. Testosterone isneeded to make sperm. Testosterone is
responsible for the development of maleresponsible for the development of male
characteristics, including muscle mass andcharacteristics, including muscle mass and
strength, fat distribution, bone mass, facial strength, fat distribution, bone mass, facial
hairhair growth, voice change, and growth, voice change, and sex drivesex drive..

16. How dose the male reproductiveHow dose the male reproductive
system its function?system its function?
 The entire male reproductive system isThe entire male reproductive system is
dependent on hormones, which aredependent on hormones, which are
chemicals that regulate the activity ofchemicals that regulate the activity of
many different types of cells or organs.many different types of cells or organs.
The primary hormones involved in theThe primary hormones involved in the
male reproductive system are follicle-male reproductive system are follicle-
stimulating hormone, stimulating hormone, luteinizing hormoneluteinizing hormone,,
and testosterone.and testosterone.

17. Formation of the spermFormation of the sperm
 Sperm is made in the male testes through aSperm is made in the male testes through a
process called spermatogenesis, whichprocess called spermatogenesis, which
develops immature cells called spermatogoniadevelops immature cells called spermatogonia
into fully mature sperm cells calledinto fully mature sperm cells called
spermatozoa. This begins in the seminiferousspermatozoa. This begins in the seminiferous
tubules, where the spermatogonia undergotubules, where the spermatogonia undergo
division in a process called mitosis. In the lastdivision in a process called mitosis. In the last
stage of maturation, called spermiogenesis, thestage of maturation, called spermiogenesis, the
sperm cell elongates, grows a tail and rotates sosperm cell elongates, grows a tail and rotates so
that its tail faces inside the tube. that its tail faces inside the tube.

18.  In the process of maturation, the head of the spermIn the process of maturation, the head of the sperm
develops a cap called the acrosome, which helps itdevelops a cap called the acrosome, which helps it
break down the wall of the female egg during fertilization.break down the wall of the female egg during fertilization.
The tail propels the sperm using an undulating motion.The tail propels the sperm using an undulating motion.
Once the sperm is fully mature, it travels through theOnce the sperm is fully mature, it travels through the
seminiferous tubules and is stored in the epididymis ofseminiferous tubules and is stored in the epididymis of
the testes until it leaves the body during ejaculation.the testes until it leaves the body during ejaculation.
 From the beginning of the process until the end, it takesFrom the beginning of the process until the end, it takes
about 70 days to make sperm. Boys begin to produceabout 70 days to make sperm. Boys begin to produce
sperm when they go through puberty. Sperm issperm when they go through puberty. Sperm is
continually produced in males, unlike women whocontinually produced in males, unlike women who
ovulate only once per month. In human males withovulate only once per month. In human males with
normal reproductive systems, every ejaculation containsnormal reproductive systems, every ejaculation contains
approximately 200 to 300 million sperm. In addition toapproximately 200 to 300 million sperm. In addition to
sperm, ejaculated semen contains a number of othersperm, ejaculated semen contains a number of other
liquids, including secretions from the seminal vesicles,liquids, including secretions from the seminal vesicles,
Cowper's gland and prostate gland.Cowper's gland and prostate gland.

20. Hormones secreted by testesHormones secreted by testes
 The main hormone secreted by the testes is testosterone, anThe main hormone secreted by the testes is testosterone, an
androgenic hormone. Testosterone is secreted by cells that lieandrogenic hormone. Testosterone is secreted by cells that lie
between the seminiferous tubules, known as the Leydig cells. Thebetween the seminiferous tubules, known as the Leydig cells. The
testes also produce inhibin B and testes also produce inhibin B and anti-Müllerian hormoneanti-Müllerian hormone from from
Sertoli cells, and insulin-like factor 3 and Sertoli cells, and insulin-like factor 3 and oestradioloestradiol from the Leydig from the Leydig
cells.cells.
 Testosterone is important in the first stages of developing the maleTestosterone is important in the first stages of developing the male
reproductive organs in a foetus. It also causes the development ofreproductive organs in a foetus. It also causes the development of
male characteristics such as growth of facial hair, deepening of themale characteristics such as growth of facial hair, deepening of the
voice and the growth spurt that takes place during puberty.voice and the growth spurt that takes place during puberty.
Testosterone is important in maintaining these secondary maleTestosterone is important in maintaining these secondary male
characteristics throughout a man’s life. From puberty onwards,characteristics throughout a man’s life. From puberty onwards,
testosterone provides the main stimulus for sperm production.testosterone provides the main stimulus for sperm production.

21.  many things can wrong with the testes; they can be grouped into physicalmany things can wrong with the testes; they can be grouped into physical
injury and diseases or conditions that affect the function of the testes:injury and diseases or conditions that affect the function of the testes:
 Physical injury - The testes lie outside of the body and are not protected byPhysical injury - The testes lie outside of the body and are not protected by
muscle and bone so any physical shock (trauma) to the testes can causemuscle and bone so any physical shock (trauma) to the testes can cause
severe pain, bruising and swelling. Usually this is not serious, but very rarelysevere pain, bruising and swelling. Usually this is not serious, but very rarely
a severe trauma can cause blood to leak into the scrotum; this is calleda severe trauma can cause blood to leak into the scrotum; this is called
testicular rupture. Surgery may be needed to repair the rupture. testicular rupture. Surgery may be needed to repair the rupture.
Another rare form of injury is a ‘twisted testicle’ or testicular torsion. This isAnother rare form of injury is a ‘twisted testicle’ or testicular torsion. This is
when the spermatic cord becomes twisted from an injury to the testis orwhen the spermatic cord becomes twisted from an injury to the testis or
after strenuous activity. It happens more often in teenage boys. This torsionafter strenuous activity. It happens more often in teenage boys. This torsion
cuts off the blood supply to the testis. This is a medical emergency andcuts off the blood supply to the testis. This is a medical emergency and
surgery is needed to untwist the cord, restore the blood supply and save thesurgery is needed to untwist the cord, restore the blood supply and save the
testis.testis.
 Diseases and conditions that affect the function of the testes - there areDiseases and conditions that affect the function of the testes - there are
many reasons for testicular dysfunction caused by diseases and conditions:many reasons for testicular dysfunction caused by diseases and conditions:
 Male infertility - due to absent or reduced sperm production or the production ofMale infertility - due to absent or reduced sperm production or the production of
sperm that do not function normally. There can be many causes includingsperm that do not function normally. There can be many causes including
genetic and lifestyle factors. There are few treatments to correct male infertilitygenetic and lifestyle factors. There are few treatments to correct male infertility
and some form of assisted reproduction may be required.and some form of assisted reproduction may be required.
 Cryptorchidism - the failure of one or both testes to drop down into the scrotumCryptorchidism - the failure of one or both testes to drop down into the scrotum
before birth, so they remain in the abdominal space. This can harm normalbefore birth, so they remain in the abdominal space. This can harm normal
development and function of the testes and lead to infertility.development and function of the testes and lead to infertility.

22. Hormones affect the formation ofHormones affect the formation of
the spermthe sperm
 GnRHGnRH is made in the is made in the hypothalamushypothalamus and travels and travels
to the pituitary where it stimulates to the pituitary where it stimulates FSHFSH and and LHLH
secretion. secretion.
 FSH is necessary for sperm maturation.FSH is necessary for sperm maturation.
 LH binds to LH binds to Leydig Leydig cellscells to stimulate to stimulate
testosteronetestosterone secretion and secretion and androgenandrogen production. production.
 Testosterone stimulates sex drive.Testosterone stimulates sex drive.
 Inhibin acts as Inhibin acts as negative feedbacknegative feedback to slow the to slow the
release of FSH and GnRH.release of FSH and GnRH.

23.  GnRHGnRH
 Gonadotropin-releasing hormone is a trophicGonadotropin-releasing hormone is a trophic
peptide hormone responsible for the release ofpeptide hormone responsible for the release of
follicle-stimulating hormone (FSH) andfollicle-stimulating hormone (FSH) and
luteinizing hormone (LH) from the anteriorluteinizing hormone (LH) from the anterior
pituitary.pituitary.
 LHLH
 Luteinizing hormone is produced by the anteriorLuteinizing hormone is produced by the anterior
pituitary gland and in males causes thepituitary gland and in males causes the
synthesis and secretion of testosterone andsynthesis and secretion of testosterone and
androgen.androgen.
 FSHFSH
 Follicle-stimulating hormone stimulates both theFollicle-stimulating hormone stimulates both the
production of androgen-binding protein byproduction of androgen-binding protein by
Sertoli cells and the formation of the blood-testisSertoli cells and the formation of the blood-testis
barrier.

24.  Gonadotropin-Releasing HormoneGonadotropin-Releasing Hormone
 Gonadotropin-releasing hormone (GnRH) is mainlyGonadotropin-releasing hormone (GnRH) is mainly
made in the preoptic area of the hypothalamus beforemade in the preoptic area of the hypothalamus before
traveling to the pituitary gland. There it stimulates thetraveling to the pituitary gland. There it stimulates the
synthesis and secretion of the gonadotropins, FSH and synthesis and secretion of the gonadotropins, FSH and
luteinizing hormoneluteinizing hormone (LH). (LH).
 Follicle-Stimulating HormoneFollicle-Stimulating Hormone
 Follicle-stimulating hormone (FSH) is released by the Follicle-stimulating hormone (FSH) is released by the
anterior pituitary glandanterior pituitary gland. Its presence in males is. Its presence in males is
necessary for the maturation of spermatozoa. Follicle-necessary for the maturation of spermatozoa. Follicle-
stimulating hormone stimulates both the production ofstimulating hormone stimulates both the production of
androgen-binding protein by Sertoli cells and theandrogen-binding protein by Sertoli cells and the
formation of the blood-testis barrier. Increasing the levelsformation of the blood-testis barrier. Increasing the levels
of FSH increases the production of spermatozoa byof FSH increases the production of spermatozoa by
preventing the apoptosis of type A spermatogonia. preventing the apoptosis of type A spermatogonia.

25.  Luteinizing HormoneLuteinizing Hormone
 Luteinizing hormone (LH) is released by the anterior pituitary gland.Luteinizing hormone (LH) is released by the anterior pituitary gland.
In the testes, LH binds to receptors on Leydig cells, whichIn the testes, LH binds to receptors on Leydig cells, which
stimulates the synthesis and secretion of testosterone. stimulates the synthesis and secretion of testosterone.
 TestosteroneTestosterone
 Testosterone is made in the interstitial cells of the testes. ItTestosterone is made in the interstitial cells of the testes. It
stimulates the sex drive and is associated with aggression.stimulates the sex drive and is associated with aggression.
Androgen-binding protein is essential to concentrating testosteroneAndrogen-binding protein is essential to concentrating testosterone
in levels high enough to initiate and maintain spermatogenesis,in levels high enough to initiate and maintain spermatogenesis,
which can be 20-50 times higher than the concentration found inwhich can be 20-50 times higher than the concentration found in
blood. The sequestering of testosterone in the testes is initiated byblood. The sequestering of testosterone in the testes is initiated by
FSH, and only testosterone is required to maintainFSH, and only testosterone is required to maintain
spermatogenesis. spermatogenesis.
 InhibinInhibin
 Inhibin is secreted by the Sertoli cells and acts to decrease theInhibin is secreted by the Sertoli cells and acts to decrease the
levels of FSH. The hormone is released into the circulation when thelevels of FSH. The hormone is released into the circulation when the
sperm count is too high.sperm count is too high.