3. KEY WORDS
• CRYPORCHIDISM:- Failure of the testicles to
descend into the scrotum.
• HYPOSPADIUS:- Failure of closure of the
urethral folds.
• HERMAPHODITISM:- A situation in which there
is incomplete formation of both female and
male sex organs.
• OCHITIS:- inflammation of the Testes
• PRIAPISM:- Uncontrolled persistent erection of
the penis resulting from neural or vascular
disease, medications, sickle cell disease,
thrombosis or leukemia.
4. KEY WORDS
• HYDROCELE:- A collection of fluid in the
tunica vaginalis of the testes and in the
spermatic cord.
• PROSTATITIS:- Inflammation of the prostate
gland.
• PROSTATISM:- An obstructive and irritative
symptom that cause increased frequency
and hesitancy in starting urination.
• BPH:-Benign prostate Hyperplasia
• MICTURITION / VOIDING: Is the process
urination
5. INTRODUCTION
The male Reproductive system can be divided
into the following parts:-
1. THE EXTERNAL GENITALIA
2. THE INTERNAL GENITALIA and
3. THE ACCESSORY GLANDS/ORGANS
6. • LIST THE ORGANS THAT
FORM THE MALE EXTERANAL
ORGANS, INTERNAL ORGANS
and ACCESSORY GLANDS
7. 1. THE EXTERNAL GENITALIA:- Consist
of the Penis and the Scrotum
2. THE INTERNAL GENITALIA:- Consist
of the
- The Testis(es)
- The Epididymis
- The Ductus(Vas) Deferens
3. THE ACCESSORY GLANDS/ORGANS:-
Consist of - - The Prostate Gland
- The Seminal vessicles
- The Bulbo-urethral Gland or
- Cowper’s gland
9. THE EXTERNAL GENITALIA CONT’D..
THE PENIS
The penis is a cylindrical organ that passes urine
and delivers sperm into the female vagina.
It consists of three parts:-
- A ROOT that attaches the penis to the
perineum,
- A BODY (shaft) that makes up the bulk of the
penis, and
- THE GLANS PENIS which is the enlarged end
of the body.
The glans penis is covered by a prepuce
(foreskin), which may be surgically removed in
a procedure called circumcision.
10. THE EXTERNAL GENITALIA CONT’D.
.
• Internally, the penis consists of three
cylindrical masses of tissue, each of which is
surrounded by a thin layer of fibrous tissue
called tunic albuginea.
• The three cylindrical masses, which function
as erectile bodies, are as follows:
• Corpus Fascia:- Outer layer of fibrous tissue
• Corpus Carvenosus:- Middle layer of
muscular tissue
• Corpus Spongiosum:- inner layer of adipose
tissue.
11. PHYSIOLOGY OF ERECTION
The middle and inner layers of the penis have
increased supply of blood vessels that
supplies blood to the penis.
During erection, parasympathetic neurons
stimulate dilation of the arteries that deliver blood
to the corpus cavernosa and spongiosum.
As a result, blood collects in these blood vessel
and causes the penis to begin to become erect
and elongated. The developing erection also
constricts the exiting veins of the penis which
occludes venous return.
This causes even more erection and firmness of
the penis.
12.
13. EJACULATION
Ejaculation occurs when sympathetic neurons
stimulate the discharge of sperm and
supporting fluids from their various sources.
During ejaculation, the sphincter muscle at the
base of the urinary bladder constricts,
preventing the passage of urine.
This allow only the sperm to pass through the
spermatic cord to the urethra.
15. FUNCTIONS OF THE PENIS
• It is the organ for micturition.
• Delivers sperm into the female
reproductive system.
• It is the also the organ for copulation.
• It signifies sex for male at birth.
17. THE EXTERNAL GENITALIA CONT’D..
THE SCROTUM
• The scrotum is a thin sac consisting of skin and
superficial fascia that hangs from the base of the
penis.
• It is a continuation of the abdominal wall skin
which gets deeply pigmented after puberty due
to increased fat deposit.
• The scrotal wall has thin skin that is formed in
folds called Rugae.
• The external scrotum positions the testes
outside the body in an environment about 3°C
below that of the body cavity
18. THE EXTERNAL GENITALIA CONT’D..
• This is necessary for the development and
storage of sperm. Two muscles help to maintain
this temperature in response to the external
conditions. (e.g- too cold or hot). These muscles
are:-
• The Dartos muscle:- located in the superficial
fascia of the scrotum and septum.
• Contraction of this smooth muscle creates
wrinkles in the scrotum skin.
• The Cremaster muscles:- extend from the internal
oblique muscle to the scrotum.
• Contraction of these skeletal muscles lifts the
scrotum closer to the body when external
temperatures are too cold, and relaxes when too
hot.
20. THE EXTERNAL GENITALIA CONT’D..
• Internally, a vertical septum divides the scrotum
into left and right compartments, each of which
encloses a testis.
FUNCTIONS OF THE SCROTUM
- Creates room for sperm morbidity and viability.
- Protects and accommodates the testes,
epididymis and vas deferens.
- Readily responds to environmental changes to
maintain a constant temperature for the testes.
- Also signifies sex at birth.
21. THE INTERNAL GENITALIA
• The internal Genitalia is composed of:-
• THE TESTES
• THE SEMINIFEROUS TUBULES
• THE EPIDIDYMIS
• VAS DEFERENS
24. THE INTERNAL GENITALIA
THE TESTES
• The Testes are a pair of two solid oval shaped
organs.
• They are suspended vertically in the scrotum by
the spermatic cord/vas deferens.
• The left testis is lower than the right because
the left spermatic cord is longer.
• The testes are enclosed by two coats:-
– The tunica vaginalis is the outer double-layer
of serous membrane surrounding each testis.
– The tunica albuginea lies inside the tunica
vaginalis and protrudes inward, dividing each
testis into compartments called lobules.
26. THE INTERNAL GENITALIA CONT’D..
• FUNCTIONS OF THE TESTES
• They help in the production and
secretion of the male sex hormone
Testosterone.
• The hormone initiates the development
of the male secondary characteristics
such as hair growth on face, chest &
back, deepening of voice, etc.
27. THE INTERNAL GENITALIA
• THE SEMINIFEROUS TUBULES:- are the sites of
sperm production (spermatogenesis) found
within the testes(Sperm-forming factories).
• The tubule is lined with spermatogenic cells,
which form sperm, and sustentacular cells
(Sertoli cells), which support the developing
sperm. Other structures include:-
I. The coiled seminiferous tubules inside each
lobule unite to form a straight tube, the tubulus
rectus.
II. The rete testis is a network of tubes formed by
the merging of the tubules from each lobule.
28. THE INTERNAL GENITALIA Cont’d.
III. The efferent ducts transport sperm out of
the testis (from the rete testis) to the
epididymis.
IV. The Interstitial cells surrounding the
seminiferous tubules secrete testosterone
and other androgen hormones.
29. THE INTERNAL GENITALIA
CONT’D..
THE EPIDIDYDIMIS
The epididymis is a comma-shaped organ that
lies adjacent to each testis.
Each of the two epididymides contains a tightly
coiled tube, called the ductus epididymis.
Here is where sperm complete their maturation
and are stored until ejaculation.
During ejaculation, smooth muscles encircling
the epididymis contract, forcing matured
sperm into the next tube, the ductus
deferens.
30. THE INTERNAL GENITALIA CONT’D..
• THE EPIDIDYMIS Cont’d..
• The walls of the ductus epididymis contain
microvilli called stereocilia that nourish sperm.
• The lower part of the epididymis is continuous
with the muscular duct to form the Vas
Deferens.
FUNCTIONS OF THE EPIDIDYMIS
• Serves as the main storage site for sperm.
• Helps in propelling sperm into the vas deferens.
32. THE INTERNAL GENITALIA CONT’D..
THE VAS DEFERENS
The ductus deferens (vas deferens) is the tube
through which sperm travel when they leave
the epididymis.
Each of the two tubes enters the abdominal
cavity, passes around the urinary bladder
and together with the duct from the seminal
vesicle to join the ejaculatory duct.
Before entering the ejaculatory duct, the
ductus deferens enlarges, forming a region
called the ampulla.
33. THE INTERNAL GENITALIA Cont’d..
VAS (DUCTUS) DEFERENS
Sperm are stored in the ductus deferens until
peristaltic contractions of the smooth
muscles surrounding the ductus force sperm
forward during ejaculation.
FUNCTIONS OF THE VAS DEFERENS
- Helps in the transportation of sperm from the
epididymis to the urethra.
- Serve as a recevoir for sperm.
- Secrets some fluid that supports the sperm.
34.
35. THE ACCESSORY GLANDS/ORGANS
• The accessory Glands/Organs of the Male
Reproductive system include:-
• THE PROSTATE GLAND
• SEMINAL VESSICLES
• BULBOURETHRAL (Cowper’s) GLAND
36. THE ACCESSORY GLANDS/ORGANS:-
THE PROSTATE GLAND
• This is the largest accessory gland of the male
reproductive system.
• It is a chestnut-shaped, glandular and fibro
muscular organ.
• It is a bi-lobed structure with a round or heart-
shaped in appearance.
• It measures 2.5cm long and 4cm in diameter.
• It lies in front of the anterior wall of the rectum
and 2cm behind the symphysis pubis.
• It surrounds the neck of the urinary bladder and
has about 15 – 30 ducts that empties into the
bladder.
37. THE ACCESSORY GLANDS/ORGANS
• FUNCTIONS OF THE PROSTATE GLAND
• It secrets a thin, milky, alkaline fluid that
helps sperm viability.
• The fluid helps to neutralize the acidity of
other seminal fluids.
• This helps to enhance sperm viability.
• The total secretion of the prostate accounts
for about 20-30% of the total ejaculation.
• Assist in the first stage of male orgasm.
38. THE ACCESSORY GLANDS/ORGANS
THE SEMINAL VESICLES
These are projections like rabbit-ears
located above the prostate and behind the
bladder.
Each seminal vesicle ends in a small duct
that joins the ampulla of vas deferens to
form the ejaculatory duct.
39. THE ACCESSORY GLANDS/ORGANS
FUNCTIONS OF THE SEMINAL VESICLES
- The seminal vesicles secrete into the vas
deferens an alkaline fluid (which
neutralizes the acid in the vagina).
- It secrets fructose (which provides energy
for the sperm).
- It also secrets prostaglandins (which
increase sperm viability and stimulate
female uterine contractions that help
sperm move into the uterus).
- It contributes about 40 – 60% of the total
ejaculate.
40. THE ACCESSORY GLANDS/ORGANS:-
THE BULBOURETHRAL GLANDS
- These are two small yellow pear-shape
glands.
- They are located below the prostate and on
either sides of the urethra.
FUNCTIONS OF THE BULBO-URETHRAL GLAND.
• The bulbo-urethral glands secrete an alkaline
fluid into the spongy urethra.
• The fluid neutralizes acidic urine in the
urethra before ejaculation occurs
• Contributes about 5-6% of the total ejaculate.
41. THE ACCESSORY
GLANDS/ORGANS CONT’D..:-
• THE URETHRA is the passageway for urine and
semen (sperm and associated secretions).
Three regions of the urethra are distinguished:
– The prostatic urethra passes through the
prostate gland.
– The membranous urethra passes through the
urogenital diaphragm (muscles associated
with the pelvic region).
– The spongy (penile) urethra passes through
the penis.
• The urethra ends at the external urethral
orifice.
42. SPERM PRODUCTION
Sperm production is called SPREMATOGENESIS.
Spermatogenesis begins at puberty within the
seminiferous tubules of the testes.
• Each spermatozoon contains 46 chromosomes,
divided by mitosis repeatedly and differentiated
to produce primary spermatocytes.
• The primary spermatocytes begin the meiosis.
• During the first meiotic cell division, each
primary spermatocytes divides into two
secondary spermatocytes, each with 23
chromosomes (haploid cells).
43. SPERM PRODUCTION Cont’d..
During the second meiotic division, each secondary
spermatocytes divides again, producing a total of
four spermatids.
Each spermatid still contains 23 chromosomes, but
these chromosomes consist of only one chromatid
(rather than the normal two chromatids).
At the end of this process, each sperm cell bears the
following structures:
The head:- This contains the haploid nucleus
with 23 chromosomes. At the tip of the sperm
head is the
Acrosome:- This is found at the tip of the sperm
head. It is a lysosome containing enzymes that
are used to penetrate the egg.
44. SPERM PRODUCTION CONT’D..
• The acrosome originates from Golgi body
vesicles that fuse to form a single lysosome.
• The midpiece is the first part of the tail. It is
surrounded by Mitochondria which produce
energy (ATP) used to generate the whiplike
movements of the tail that propel the sperm.
The tail is a flagellum consisting of the typical
9 + 2 microtubule arrays.
• The production of sperm is regulated by
hormones.
45. SPERM PRODUCTION CONT’D…
• The hypothalamus begins secreting
gonadotropin releasing hormone (GnRH) at
puberty.
• GnRH stimulates the anterior pituitary to
secrete follicle stimulating hormone (FSH)
and luteinizing hormone (LH).
• LH stimulates the interstitial cells in the
testes to produce testosterone and other
male sex hormones (androgens).
• Testosterone stimulates the final stages of
sperm development in the nearby
seminiferous tubules
46. SPERM PRODUCTION CONT’D..
Testosterone entering the blood circulates
throughout the body, where it stimulates the
activity of the prostate gland, seminal
vesicles, and various other target tissues.
Testosterone and other androgens stimulate
the development of secondary sex
characteristics, those characteristics not
directly involved in reproduction.
These include the distribution of muscle and
fat typical in adult males, various body hair
(facial and pubic hair) and deepening of the
voice.
