1. Anatomy ASSIGNMENT
MALE REPRODUCTIVE SYSTEM
NAME: TOOBA REHMAN
CLASS: FIRST PROF. YEAR
ROLL NO. : 100
Group: 16 (B)
COURSE NAME: ANATOMY
COURSE CODE: 317
COURSE INCHARGE: dr. safoora tariq
2. INTRODUCTION
REPRODUCTION
The process in which one or two parent organisms form a new individual is called
reproduction and the organs involve in reproduction are collectively called
reproductive system.
MALE REPRODUCTIVE SYSTEM
Genital organs of a male body include in reproductive system are collectively called
male reproductive system. Male reproductive system consist of f0llowing organs
named below.
1) Testes
2) Scrotum
3) Seminal vesical
4) Prostate gland
5) Cowper’s gland
6) Epididymis
7) Vas deferens
8) Spermatic cord
9) Urinogenital duct
10) Penis
3. EXPLANATION
TESTES
(singular=Testis)
Testes are r0ugh egg like in shape and about 3 cm long contain a mass of
semineferous tubules that manufacture the male sperm cell called
Spermatozoa. The testes (TES-teÂŻz), or testicles, are paired oval glands in
the scrotum measuring about 5 cm long and 2.5 cm in diameter . Each testis
(singular) has a mass of 10–15 grams. The testes develop near the kidneys, in
the posterior portion of the abdomen, and they usually begin their descent
into the scrotum through the inguinal canals (passage-ways in the anterior
abdominal wall;) during the latter half of the seventh month of fetal
development.A serous membrane called the tunica vaginalis (tunica
sheath), which is derived from the peritoneum and forms during
the descent of the testes, partially covers the testes. A collection
of serous fluid in the tunica vaginalis is called a hydrocele.
SCROTUM
The scrotum(SKRO-tum = bag), the supporting structure for the
testes, consists of loose skin and underlying subcutaneous layer that
hangs from the root (attached portion) of the penis .Externally, the scrotum
looks like a single pouch of skin separated into lateral portions by a median
ridge called the raphe (RA—fe= seam). Internally, the scrotal septumdivides
the scro-tum into two sacs, each containing a single testis .The septum is
made up of a subcutaneous layer and muscle tissue called the dartos muscle
(DAR-tos =skinned), which is composed of bundles of smooth muscle fibers.
The dartos muscle is also found in the subcutaneous layer of the
scrotum. Associated with each testis in the scrotum is the
cremaster muscle(kre-MAS-ter = suspender), a series of small
bands of skeletal muscle that descend as an extension of the internal
oblique muscle through the spermatic cord to surround the testes.
4. SEMINAL VESICAL
The paired seminal vesicles(VES-i-kuls) or seminal glandsare convoluted
pouchlike structures, about 5 cm in length, lying posterior to the base of the
urinary bladder and anterior to the rectum. Seminal vesical produces much
of the seminal fluid and lies lateral to the ductus on the posterior wall of
the bladder with its upper end just below the p0int of enterance of ureter
into the bladder. The very short duct leaves the l0wer end to join the
ductus deference at the edge of the prostate gland and form the
ejaculat0ry duct.
PROSTATE GLAND
The prostate (PROS-ta t) is a single, doughnut-shaped gland
about the size of a golf ball. It measures about 4 cm from
side to side, about 3 cm from top to bottom, and about 2 cm
from front to back. It is inferior to the urinary bladder and
surrounds the prostatic urethra . The prostate slowly increases
in size from birth to puberty. It then expands rapidly until about
age 30, after which time its size typically remains stable until about
age 45, when further enlargement may occur. Prostate consist of glands
embedded in a mass of connective tissues and smooth muscle. It secrets
about 30% of seminal fluid.
COWPER’s GLAND
The paired bulbourethral glands (bul-bo -u -RE--thral), or
Cowper’s glands are about the size of peas. They are located
inferior to the prostate on either side of the membranous urethra
within the deep muscles of the perineum, and their ducts open into the
spongy urethra .
5. EPIDIDYMIS
The epididymis(ep-i-DID-i-mis; epi- above or over; -didymis=testis)
is a comma-shaped organ about 4 cm long that lies along the posterior
border of each testis.The plural is epididymides (ep-i-did-IM-i-des).
Each epi-didymis consists mostly of the tightly coiled ductus epididymis.
The efferent ducts from the testis join the ductus epididymis at
the larger, superior portion of the epididymis called the head.
The bodyis the narrow midportion of the epididymis, and the
tail is the smaller, inferior portion. At its distal end, the tail of
the epididymis continues as the ductus (vas) deferens .The ductus
epididymis would measure about 6 m in length if it were uncoiled.
It is lined with pseudostratified columnar epithelium and encircled
by layers of smooth muscle.
The free surfaces of the columnar cells contain stereocilia,
which despite their name are long, branching microvilli (not
cilia) that increase the surface area for the reabsorption of degenerated
sperm. Connective tissue around the muscle layer attaches the loops of the
ductus epididymis and carries blood vessels and nerves.
VAS (DUCTUS) DEFERENS
Within the tail of the epididymis, the ductus epididymis becomes less
convoluted, and its diameter increases. Beyond this point, the duct is
known as the ductus deferens 0R vas deferens.The ductus deferens,
which is about 45 cm long, ascends along the posterior border of the
epididymis through the spermatic cord and then enters the pelvic
cavity. There it loops over the ureter and passes over the side and
down the posterior surface of the urinary bladder. The dilated
terminal portion of the ductus deferens is the ampulla (am-PUL-la
= little jar). The mucosa of the ductus deferens consists of
pseudostratified columnar epithelium and lamina propria (areolar
connective tissue). The muscularis is composed of three layers of
smooth muscle; the inner and outer layers are longitudinal, and the
middle layer is circular.
6. SPERMATIC CORD
The collective name f0r the ductus deferens, the testicular and 0ther
vessels and nerves and various connective tissue c0verings derived from the
abd0minal musculature that f0rm the inguinal canal.
The spermatic cordis a supporting
structure of the male repro-ductive system that ascends out of the
scrotum. It consists of the ductus (vas) deferens as it ascends through
the scrotum, the testicular artery, veins that drain the testes and carry
testosterone into circulation (the pampiniform plexus), autonomic nerves,
lymphatic vessels, and the cremaster muscle. The spermatic cord and
ilioinguinal nerve pass through the inguinal canal (IN-gwin-al =groin), an
oblique passageway in the anterior abdominal wall just superior and
parallel to the medial half of the inguinal ligament. The canal, which is
about 4–5 cm long, originates at the deep (abdominal) inguinal ring,a
slit like opening in the aponeurosis of the transversus ab-dominis muscle; the
canal ends at the superficial (subcutaneous) inguinal ring, a somewhat
triangular opening in the aponeurosis of the external oblique muscle. In
females, the round ligament of the uterus and ilioinguinal nerve
pass through the inguinal canal.
7. URINOGENITAL DUCT
In males, the urethrais the shared terminal duct of the reproductive and
urinary systems; so it is also kn0wn as urinogenital duct.
It serves as a passageway for both semen and urine. About 20 cm long, it
passes through the prostate, the deep muscles of the perineum, and the
penis, and is subdivided into three parts . The prostatic urethrais 2–3 cm
long and passes through the prostate. As this duct continues inferiorly, it
passes through the deep muscles of the perineum, where it is known as the
membranous urethra.The membranous urethra is about 1 cm in length. As
this duct passes through the corpus spongiosum of the penis, it is known as
the spongy (penile) urethra,which is about 15–20 cm long. The spongy urethra
ends at the external urethral orifice.
PENIS
The peniscontains the urethra and is a passageway for the ejaculation of
semen and the excretion of urine . It is cylindrical in shape and consists of a
body, glans penis, and a root. The body of the penisis composed of three
cylindrical masses of tissue, each surrounded by fibrous tissue called the
tunica albuginea . The two dorsolateral masses are called the corpora
cavernosa penis(corpora=main bod-ies; cavernosa =hollow). The smaller
midventral mass, the corpus spongiosum penis, contains the spongy urethra
and keeps it open during ejaculation. Skin and a subcutaneous layer enclose
all three masses, which consist of erectile tissue. Erectile tissue is
composed of numerous blood sinuses (vascular spaces) lined by endothelial
cells and surrounded by smooth muscle and elastic connective tissue.
8. BLOOD SUPPLY TO THE MALE REPRODUCTIVE
ORGANS :FOR TESTES AND EPIDIDYMIS: Internal to the tunica albuginea is the
tunica vasculosa, containing a plexus of blood vessels and connective tissue.
Bilateral testicular arteries originating from the aorta, just inferior to the
renal arteries, provide arterial supply to the testes. The testicular arteries
enter the scrotum in the spermatic cord via the inguinal canal and split into
two branches at the posterosuperior border of the testis. Additionally, the
testes receive blood from the cremasteric branch of the inferior epigastric
artery and the artery to the ductus deferens. The pampiniform plexus
drains both the testis and epididymis before coalescing to form the
testicular vein, usually above the spermatic cord formation at the deep
inguinal ring. The tenth and eleventh thoracic spinal nerves supply the testes
via the renal and aortic autonomic plexuses. Blood supply for epididymis is
same as for testes.
FOR PROSTATE GLAND: The arterial supply to the prostate gland is
derived from the inferior vesical artery and branches of the middle rectal
artery. Venous drainage of the prostate forms the prostatic plexus, which
eventually drains into the internal iliac vein
FOR SEMINAL VESICLES AND COWPER’s GLAND: Arterial blood supply
to the seminal vesicles includes branches from the inferior vesical and
middle rectal arteries, while venous accompanies these arteries. The inferior
division of the hypogastric plexus provides innervation to the seminal
vesicles. Blood supply for cowper’s gland is same as for seminal vesicles.
FOR DUCTUS DEFERENS AND URINOGENITAL DUCT: Each ductus
deferens has an artery usually derived from the superior vesical artery
(artery to the ductus), with venous drainage to the pelvic venous plexus.
Same blood supplying process for urinogenital duct.
9. FOR PENIS: The vasculature of the penis is extensive. The perineal artery (a
branch of the internal pudendal artery) together with the posterior scrotal artery
and the inferior rectal artery supply tissues from the bulb of the penis to the
anus. The artery of the bulb of the penis, from the internal pudendal, penetrates
the penile bulb and subsequently supplies the corpus spongiosum. The deep artery
of the penis is one of two terminal branches of the internal pudendal artery; it
enters the crus of the penis and continues through the length of the bilateral
corpus cavernosum. The other terminal branch of the internal pudendal artery is
the dorsal artery of the penis running along the dorsal surface of the penis
supplying the penile skin and the glans penis.
The venous drainage of the penis includes the veins draining the corpora cavernosa,
which subsequently drains into the circumflex veins. These veins receive venous
blood from the corpus spongiosum on the ventral aspect of the penis and wrap
around the penis to drain into the deep dorsal vein. The superficial dorsal vein
drains the penile skin and prepuce before draining via the superficial external
pudendal vein into the external pudendal veins. The deep dorsal vein further drains
blood from the glans penis and corpora cavernosa before joining the prostatic
venous plexus.