MALE REPRODUCTIVE SYSTEM

1. ANATOMY OF MALE
REPRODUCTIVE SYSTEM

2. PARTS OF MALE REPRODUCTIVE SYSTEM
The external structures of male reproductive system include:
 The penis
 The scrotum
 The testicles &Epididymis
The internal organs of the male reproductive system, also called
accessory organs, include the following:
 Vas deferens
 Ejaculatory ducts
 Urethra
 Seminal vesicles
 Prostate gland
 Bulbourethral glands

3. The penis
The penis is an external organ of the male
reproductive system.
STRUCTURE OF THE PENIS
The penis can be anatomically divided into
three parts:
Root – the most proximal, fixed part of the
penis.
• It is located in the superficial perineal
pouch of the pelvic floor, and is not
visible externally.
• The root contains three erectile tissues
(two crura and bulb of the penis), and
two muscles (ischiocavernosus and
bulbospongiosus).

4. • Body – the free part of the penis, located between
the root and glans. It is suspended from the pubic
symphysis. It is composed of three cylinders of
erectile tissue – two corpora cavernosa, and the
corpus spongiosum.
• Glans – the most distal part of the of penis. It is
conical in shape, and is formed by the distal
expansion of the corpus spongiosum. This contains
the opening of the urethra, termed the external
urethral orifice.

5. Erectile Tissues
• The erectile tissues fill with blood during sexual arousal,
producing an erection. The root and body of the penis
are spanned by three masses of erectile tissue.
• In the root, these tissues are known as the left and
right crura, and the bulb of the penis. The bulb is
situated in the midline of the penile root, and is
traversed by the urethra. The left and right crura are
located laterally; attached to the ipsilateral ischial
ramus, and covered by the paired ischiocavernosal
muscles.

6. • The erectile tissues continue into the body
of the penis. The left and right crura
continue anteriorly into the dorsal part of
the penis – they form the two corpora
cavernosa. They are separated by the
septum of the penis, although often
incompletely.

7. • The bulb forms the corpus
spongiosum, which lies
ventrally. The male urethra
runs through the corpus
spongiosum – to prevent it
becoming occluded during
erection the corpus
spongiosum fills to a reduced
pressure.
• Distally, the corpus
spongiosum expands to form
the glans penis.
The erectile tissues of the penis.

8. Muscles
• There are four muscles located in the root of the
penis:
• Bulbospongiosus (x2) – associated with the bulb of
the penis. It contracts to empty the spongy urethra
of any residual semen and urine.
• Ischiocavernosus (x2) – surrounds the left and right
crura of the penis. It contracts to force blood from
the cavernous spaces in the crura into the corpus
cavernosa – this helps maintain erection.

9. Ligaments
• The root of the penis is supported by two ligaments,
which attach it to the surrounding structures:
• Suspensory ligament – a condensation of deep
fascia. It connects the erectile bodies of the penis to
the pubic symphysis.
• Fundiform ligament – a condensation of abdominal
subcutaneous tissue. It runs down from the linea
alba, surrounding the penis like a sling, and attaching
to the pubic symphysis.

10. • Skin
• The skin of the penis is more heavily pigmented than
that of the rest of the body. It is connected to the
underlying fascias by loose connective tissue.
• The prepuce (foreskin) is a double layer of skin and
fascia, located at the neck of the glans. It covers the
glans to a variable extent. The prepuce is connected
to the surface of the glans by the frenulum, a median
fold of skin on the ventral surface of the penis.

11. Neurovascular Supply
Vasculature
• The penis receives arterial supply from three sources:
• Dorsal arteries of the penis
• Deep arteries of the penis
• Bulbourethral artery
• These arteries are all branches of the internal pudendal
artery. This vessel arises from the anterior division of
the internal iliac artery.

12. Venous drainage:
Venous blood is drained from the penis by paired veins. The
cavernous spaces are drained by the deep dorsal vein of
the penis – this empties into the prostatic venous plexus
. The superficial dorsal veins drain the superficial structures
of the penis, such as the skin and cutaneous tissues.
Nerve Innervation:
• The penis is supplied by S2-S4 spinal cord segments and
spinal ganglia.
• Sensory and sympathetic innervation to the skin and glans
penis is supplied by the dorsal nerve of the penis, a branch
of the pudendal nerve.

13. Clinical Relevance
Paraphimosis
• Paraphimosis is an acute condition that occurs when
a tight prepuce is left retracted under the glans: this
may cause oedema of the soft prepuce and further
strangulation occurs.

14. Scrotum
• The scrotum is a fibromuscular cutaneous sac,
located between the penis and anus. It is dual-
chambered, forming an expansion of the
perineum.
• Embryologically, the scrotum is derived from
the paired genital swellings. During
development, the genital swellings fuse in the
midline – in the adult this fusion is marked by
the scrotal raphe. The scrotum is biologically
homologous to the labia majora.

15. The scrotum, muscle layer and contents

16. Neurovascular Supply
• Vessels
• The scrotum receives arterial supply from the
anterior and posterior scrotal arteries. The anterior
scrotal artery arises from the external pudendal
artery, while the posterior is derived from the
internal pudendal artery.
• The scrotal veins follow the major arteries, draining
into the external pudendal veins.
• Nerves

17. • Cutaneous innervation to the scrotum is supplied via
several nerves, according to the topography:
• Anterior and anterolateral aspect – Anterior scrotal
nerves derived from the genital branch of
genitofemoral nerve and ilioinguinal nerve
• Posterior aspect – Posterior scrotal nerves derived
from the perineal branches of the pudendal nerve
and posterior femoral cutaneous nerve.

18. • Lymphatics
• The lymphatic fluid from the scrotum drains to the
nearby superficial inguinal nodes.
CLINICAL RELEVANCE:
Haematoma of the Scrotum
• A haematoma may develop in the scrotum as a result
of scrotal surgery or trauma in the genital region.
• This results in swelling (oedema) and discolouration
of the scrotal skin.

19. The Testes and Epididymis
The testes and epididymis are paired structures, located
within the scrotum. The testes are the site of sperm
production and hormone synthesis, while the epididymis
has a role in the storage of sperm.
ANATOMICAL POSITION:
The testes are located within the scrotum, with the
epididymis situated on the posterolateral aspect of each
testicle.
Originally, the testes are located on the posterior
abdominal wall. During embryonic development they
descend down the abdomen, and through the inguinal
canal to reach the scrotum

20. The testes and epididymis, surrounded by the tunica
vaginalis.

21. Anatomical Structure
• The testes have an ellipsoid shape. They consist of a
series of lobules, each containing seminiferous
tubules supported by interstitial tissue. The
seminiferous tubules are lined by Sertoli cells that aid
the maturation process of the spermatozoa.
• Spermatozoa are produced in the seminiferous
tubules. The developing sperm travels through the
tubules, collecting in the rete testes.
• Inside the scrotum, the testes are covered almost
entirely by the tunica vaginalis, a closed sac of parietal
peritoneal origin that contains a small amount of
viscous fluid

22. • The testicular parenchyma is protected by the tunica
albuginea, a fibrous capsule that encloses the testes.
• The epididymis consists of a single heavily coiled duct. It
can be divided into three parts; head, body and tail.
• Head – The most proximal part of the epididymis. It is
formed by the efferent tubules of the testes, which
transport sperm from the testes to the epididymis.
• Body – Formed by the heavily coiled duct of the
epididymis.
• Tail – The most distal part of the epididymis. It marks the
origin of the vas deferens, which transports sperm to the
prostatic portion of the urethra for ejaculation.
•

23. Structure of the testes and epididymis

24. Vascular Supply
ARTERIAL SUPPLY: paired testicular arteries, which
arise directly from the abdominal aorta.
• Testes are also supplied by branches of the
cremasteric artery (from the inferior epigastric
artery) and the artery of the vas deferens (from the
inferior vesical artery).
VENOUS DRAINAGE: Paired testicular veins. They are
formed from the pampiniform plexus in the scrotum
– a network of veins wrapped around the testicular
artery.

25. INNERVATION:
The testes and epididymis receive innervation from the
testicular plexus – a network of nerves derived from
the renal and aortic plexi. They receive autonomic
and sensory fibres.
LYMPHATICS:
The lymphatic drainage is to the lumbar and para-
aortic nodes, along the lumbar vertebrae.
• This is in contrast to the scrotum, which drains into
the nearby superficial inguinal nodes.

26. Clinical Relevance
• Inguinal hernia – where the contents of the abdominal
cavity protrude into the scrotum, via the inguinal canal.
• Hydrocoele – a collection of serous fluid within the tunica
vaginalis. The congenital form is most commonly due to a
failure of the processus vaginalis to close. Adult hydrocele
is often associated with inflammation or trauma and
rarely, testicular tumors.
• Haematocoele – a collection of blood in the tunica
vaginalis. It can be distinguished from a hydrocoele
by transillumination (where a light is applied to the
testicular swelling).

27. • Varicocoele – gross dilation of the veins draining the
testes. The left testicle is more commonly affected,
as the left testicular vein is longer and drains into the
left renal vein at a perpendicular angle.
• Epididymitis – inflammation of the epididymis,
usually caused by bacterial or viral infection

28. INTERNAL ORGANS/ACCESSORY ORGANS
• 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.
• 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, allowing only semen to
be ejaculated at orgasm.

29. Inferior view of the structures in the male
reproductive system.

30. The Seminal Vesicles
The seminal vesicles (also
known as the vesicular or
seminal glands) are a pair
of glands found in the
male pelvis, which
function to produce many
of the constituent
ingredients of semen.
They ultimately provide
around 70% of the total
volume of semen. Anatomical position of the seminal
vesicles in relation to the vas deferens
and prostate.

31. Anatomical Position and Structure
• The seminal glands are a pair of 5cm long tubular
glands. They are located between the
bladder fundus and the rectum (separated from
the latter by the rectovesicle pouch and the
rectoprostatic fascia).
• Their most important anatomical relation is with
the vas deferens, which combine with the duct of
the seminal vesicles to form the ejaculatory duct,
which subsequently drains into the prostatic
urethra.

32. • Internally the gland has a honeycombed, lobulated
structure with a mucosa lined by pseudostratified
columnar epithelium. These columnar cells are highly
influenced by testosterone, growing taller with higher
levels, and are responsible for the production of seminal
secretions.
Embryology
• The Seminal glands, along with the Ejaculatory ducts,
Epididymis and Ductus (vas) deferens, are derived from
the mesonephric ducts, the precursor structure of male
internal genitalia.

33. VASCULATURE
• The arteries to the seminal gland are derived from
the inferior vesicle, internal pudendal and middle
rectal arteries, all of which stem from the internal
iliac artery.
Innervation:The innervation of the gland, like much of
the male internal genitalia, is mainly sympathetic in
origin.
Lymphatic Drainage
• The lymphatic drainage of the gland is the external
and internal iliac lymph nodes.

34. The Prostate Gland
• The prostate is the largest accessory gland in the
male reproductive system.
• It secretes proteolytic enzymes into the semen,
which act to break down clotting factors in the
ejaculate. This allows the semen to remain in a fluid
state, moving throughout the female reproductive
tract for potential fertilisation.

35. Anatomical Position
• The prostate is positioned inferiorly to the neck of
the bladder and superiorly to the external urethral
sphincter, with the levator ani muscle lying
inferolaterally to the gland.
• The proteolytic enzymes leave the prostate via
the prostatic ducts. These open into the prostatic
portion of the urethra, through 10-12 openings at
each side of the seminal colliculus (or
verumontanum); secreting the enzymes into the
semen immediately before ejaculation.

36. Anatomical Structure
• The prostate is commonly described as being the size
of a walnut.
• Roughly two-thirds of the prostate is glandular in
structure and the remaining third is fibromuscular.
The gland itself is surrounded by a thin fibrous
capsule of the prostate.
• This is not a real capsule; it rather resembles the thin
connective tissue known as adventitia in the large
blood vessels.

37. • More important clinically
is the histological division
of the prostate into three
zones
• Central zone – surrounds
the ejaculatory ducts,
comprising approximately
25% of normal prostate
volume.The ducts of the
glands from the central
zone are obliquely
emptying in the prostatic
urethra, thus being rather
immune to urine reflux. The anatomical position and zones of the
prostate

38. • Transitional zone – located centrally and surrounds the
urethra, comprising approximately 5-10% of normal
prostate volume.
• The glands of the transitional zone are those that typically
undergo benign hyperplasia (BPH)
• Peripheral zone – makes up the main body of the gland
(approximately 65%) and is located posteriorly.The ducts of
the glands from the peripheral zone are vertically emptying
in the prostatic urethra; that may explain the tendency of
these glands to permit urine reflux.
• The fibromuscular stroma (or fourth zone for some) is
situated anteriorly in the gland. It merges with the tissue of
the urogenital diaphragm.

39. Vasculature
The arterial supply to the prostate comes from the prostatic
arteries, which are mainly derived from the internal iliac
arteries. Some branches may also arise from the internal
pudendal and middle rectal arteries.
• Venous drainage of the prostate is via the prostatic venous
plexus, draining into the internal iliac veins.
• Innervation
• The prostate receives sympathetic, parasympathetic and
sensory innervation from the inferior hypogastric plexus.
The smooth muscle of the prostate gland is innervated by
sympathetic fibres, which activate during ejaculation.

40. Clinical Relevance -
• Prostatic Carcinoma: Prostatic carcinoma represents the
most commonly diagnosed cancer in men, especially in
countries with high sociodemographic index. The malignant
cells commonly originate from the peripheral zone,
although carcinomas may arise (more rarely) from the
central and transition zones too. It is still debatable that the
latter tumors may present with lower malignant potential.
• However the proximity of the peripheral zone to the
neurovascular bundle that surrounds the prostate may
facilitate spread along perineural and lymphatic pathways,
thus increasing the metastatic potential of these tumors.

41. • Benign Prostatic Hyperplasia (BPH)
• Benign prostatic hyperplasia is the increase in size of
the prostate, without the presence of malignancy. It
is much more common with advancing age, although
initial histological evidence of hyperplasia may be
evident from much earlier ages (<40 yrs old).
• PROSTATIS :Inflammation of the prostate

42. The Bulbourethral Glands
• The bulbourethral glands (also
known as Cowper’s glands) are a
pair of pea shaped exocrine
glands located posterolateral to
the membranous urethra. They
contribute to the final volume of
semen by producing a lubricating
mucus secretion.
• Anatomical Position and
Structure:
• the bulbourethral glands can be
found in the deep perineal pouch
of the male. Anatomical position of the bulbourethral
gland.

43. • They are situated posterolaterally to the membranous
urethra and superiorly to the bulb of the penis. Anatomical
position of the bulbourethral gland.
• The ducts of the gland penetrate the perineal membrane
alongside the membranous urethra and open into the
proximal portion of the spongy urethra.
• The glands themselves can be described as compound
tubulo-alveolar glands lined by columnar epithelium.
Embryology
• Embryologically the bulbourethral glands are derived from
the urogenital sinus, along with the bladder, prostate and
urethra. Their development is greatly influenced by DHT
(dihydrotestosterone).

44. VASCULATURE
• The arterial supply of the bulbourethral glands is derived
from the arteries to the bulb of the penis.
• Innervation
• In a mammal study (in pigs), neurons projecting to the
bulbourethral glands were found in pelvic ganglia (PG),
sympathetic chain ganglia (L2–S3), the caudal mesenteric
ganglion and dorsal root ganglia (L1–L3, S1–S3);
• They reach the bulbourethral glands via the the
hypogastric nerve and the pelvic nerve or pelvic branch of
the pudendal nerve.

45. Lymphatics
• Like the seminal vesicles the
bulbourethral glands drain into the
internal and external iliac lymph nodes