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Male reproductive system
consists of the testes and a series of ducts
and glands
Sperm are produced in the testes and are
transported through the reproductive
ducts: epididymis , ductus deferens,
ejaculatory duct, and urethra
The reproductive glands produce
secretions that become part of the semen,
the fluid that is ejaculated from the urethra
testes
are located in the scrotum, a sac of skin
between the upper thighs.
The temperature.
in the male fetus, the testes develop near
the kidneys, then descend into the
scrotum just before birth.
Cryptorchidism is the condition in which
the testes fail to descend ( sterility)
Normal sperm production requires a temperature
about 2–3C below core body temperature
Each testis is about 1.5 inches long by 1
inch wide (4cm X2.5cm)
divided internally into lobes.
Each lobe contains several seminiferous
tubules, in which spermatogenesis takes
place.
Layers of testes:
1- tunica vaginalis: serous membrane which is derived from the peritoneum
and forms during the descent of the testes
2- tunica albuginea : white fibrous capsule composed of dense irregular connective
tissue; it extends inward, forming septa that divide the testis into lobules. Each of
the 200–300 lobules contains one to three tightly coiled tubules, the seminiferous
tubules , where sperm are produced.
tunica vaginalis
tunica albuginea
Blood supply
Lymphatic drainage
In the spaces between adjacent seminiferous
tubules are clusters of cells called Leydig
(interstitial) cells . These cells secrete
testosterone
Spermatogenesis
the process of meiosis as it takes place in the testes, the site of sperm production. Within each testes are the seminiferous tubules that contain spermatogonia, or sperm-generating cells. These cells divide first by mitosis to produce primary spermatocytes.
For each primary spermatocyte that undergoes meiosis, four functional sperm cells are produced.
spermatogenesis takes 65–75 days.
spermatogonium
spermatid
sperm
1ry spermatocyte
2ndry spermatocyte
Spermiogenesis
- The final stage of spermatogenesis
- is the development of haploid spermatids into sperm
- No cell division occurs in spermiogenesis; each spermatid becomes a
single sperm cell
- During this process, spherical spermatids transform into elongated,
slender sperm.
Sperm
The head contains the 23 chromosomes.
the acrosome, On the tip of the head is
which contains enzymes to digest the
membrane of an egg cell.
Within the middle piece are mitochondria
that produce ATP.
The flagellum provides motility,requires
ATP.
Sperm from the seminiferous tubules enter
a tubular network called the rete testis,
then enter the epididymis, the first of the
reproductive ducts.
epididymis
a tube about 20 feet (6 m) long
coiled on the posterior surface of each
testis.
the sperm complete their maturation
Smooth muscle in the wall of the
epididymis propels the sperm into the
ductus deferens.
It is lined with pseudostratified columnar epithelium and encircled by layers of
smooth muscle. The free surfaces of the columnar cells contain stereocilia (long,
branching microvilli that increase the surface area for the reabsorption of
degenerated sperm.
the epididymis is the site of sperm maturation
Ductus deferens
vas deferens – cordlike
extends from the epididymis into the abdominal cavity through the inguinal canal. 45 cm
This canal is an opening in the abdominal wall for the spermatic cord, a connective tissue sheath that contains the ductus deferens, testicular blood vessels and nerves
extends upward over the urinary bladder, then down the posterior side to join the ejaculatory duct on its own side.
The smooth muscle layer of ductus deferens contracts in waves of peristalsis as part of ejaculation.
The dilated terminal portion of the ductus deferens is the
ampulla
Inguinal canal
Oblique passageway through the lower
anterior abdominal wall
In male; allow structures to pass to and
from the testes
In female; permits the passage of round
ligament of uterus
Transmit ilioinguinal nerves in both sexes
About 1.5 inch
From deep inguinal ring to medially the
superficial inguinal ring
deep (abdominal) inguinal ring, a slitlike opening in the aponeurosis of the transversus
abdominis muscle; the canal ends at the superficial (subcutaneous) inguinal ring, a
triangular opening in the aponeurosis of the external oblique muscle.
Spermatic cord
The collection of structures passing
through inguinal canal
Covered by three concentric layers of
fascia
contents
Vas deferens
Testicular A
Testicular V ( pampiniform plexus)
Testicular lymph
Autonomic nerves
Remains of processus vaginalis
Cremastric A
A of vas deferens
Genital branch of genitofemoral n
Coverings
External spermatic fascia (derived from external
abdominal muscle)
Cremasteric fascia (derived from internal abdominal
muscle)
Internal spermatic fascia (derived from transversalis
fascia)
Sperm production begins at puberty (10-
14 years), and millions of sperm are
formed each day in the testes.
Ejaculatory ducts
Each of the two ejaculatory ducts receives
sperm from the ductus deferens and the
secretion of the seminal vesicle on its own
side.
is formed by the union of the duct from the
seminal vesicle and the ampulla of the
ductus (vas) deferens
Both ejaculatory ducts empty into the
single urethra.
Seminal vesicles
lobulated organs about 2 inches long
The paired seminal vesicles are posterior
to the urinary bladder.
fructose → energy
alkaline → sperm motility.
Their upper ends are widely separated
and their lower ends are close together
Prostate gland
A muscular gland /conical
surrounds the first inch of the urethra
lies between the neck of the bladder
above and the urogenital diaphragm
Milky fluid containing citric acid and acid
phosphatase
The smooth muscle of the prostate gland
contracts during ejaculation to contribute
to the expulsion of semen from the
urethra.
Structure of prostate
divided into five lobes.
The anterior lobe
The median or middle lobe
The posterior lobe
The right and left lateral lobes
Ant ----symphysis pubis
Post--- ampulla of rectum
Sup----neck of bladder
Inf----urogenital diaphragm
Bulbourethral glands
Also called Cowper's glands
are located below the prostate gland
empty into the urethra.
Their alkaline secretions coats the interior
of the urethra just before ejaculation,
which will neutralize any acidic urine that
might be present.
Semen
consists of sperm and the secretions of
the seminal vesicles, prostate gland, and
bulbourethral glands
its average pH is about 7.4.
approximately 2-4 ml of semen is expelled.
Each milliliter of semen contains about
100 million sperm cells.