Male Reproductive System
• Consists of the testes
contained in the scrotum,
the genital ducts and their
associated glands
(accessory glands) and the
penis.
• Testes function to produce
spermatozoa (sperm) and
to synthesize the hormone
testosterone.
• Major accessory glands
include the paired seminal
vesicles and the single
prostate gland.
• Minor accessory glands include the two
bulbourethral glands located at the root of the penis.
• Accessory glands function to manufacture the fluid
portion of the semen, which transports and
nourishes the spermatozoa as they pass through the
excretory ducts.
• Penis is the male copulatory organ that delivers
spermatozoa into the female reproductive tract and
serves as a conduit for excretion of urine from the
body.
Fig 22-1 (Text)
Bladder
Prostate
Menbranous urethra
Ampulla
Seminal vesticle
Urethra
Ejaculatory duct
Penis
Bulbourethral gland
Corpus cavernosum
of the penis
Ductus deferens
Ductus epididymids
Corpus cavernosum
of the urethra
Prepuce
Glands penis
Ductus efferentes
Epididymis
Testicular lobule
Tunicia albuginea
Mediastinum
testis
Tunicia vaginalis
Tubuli recti
Rete testis
Testes
Testis
• Is an ovoid body, about 4 to 5cm long, that is
housed within the scrotum.
• Develops retroperitoneally in the abdominal
cavity and descends into the scrotum,carrying
parietal and visceral layers of the peritoneum
(the tunica vaginalis) that partially cover the
testis on its anterior and lateral surfaces.
Tunica
albuginea
Blood vessel
septum
Seminiferous
epithelium
Tunica
vasculosa
Lumen
Seminiferous
tubules
Tunica Albuginea
• Is the thick fibrous connective tissue capsule of
the testis.
• Is thickened posteriorly to form the mediastinum
testis from which connective tissue septa arise to
divide the organ into approximately 250
compartments (lobuli testis).
Tunica albuginea
Seminiferous tubules
Seminiferous epithelium
Seminiferous Tubules
• Are the sites where spermatozoa are produced.
• Are 30 to 70 cm long, with a diameter of 150 to
250 um.
• Are lined by a complex, stratified epithelium.
• Are enveloped by a fibrous connective tissue tunic,
composed of several layers of fibroblasts. Myoid
cells, resembling smooth muscle, are present in the
inner layer of some species, but not in humans.
• Form tortuous pathways through the organ before
they become continuous with the short straight
tubuli recti.
Seminiferous Epithelium
• Is composed of two different types of cells, the
spermatogenic cells from which the germ cells
eventually develop and the Sertoli cells, which
support and provide nutrition to the spermatogenic
cells.
• Is 4 to 8 cell layers thick.
Cytoplasmic bridges
Late spermiogenesis
Early spermatids
Initial spermiogenesis
Secondary
spermatocytes
meiosis
Primary
spermatocyte
Basal lamina
spermatogonium
fibroblast
Interstitial cells
Figure 22–4. Part of a seminiferous tubule with its surrounding tissues.
The seminiferous epithelium is formed by 2 cell populations: the cells of
the spermatogenic lineage and the supporting or Sertoli cells.
Sertoli cell
• Tall cells with their bases
resting over the basal
lamina of the tubule
• The cell outline is irregular,
with several infoldings.
• Cytoplasm with a reticular
appearance, with lipid
droplets, granules, and
spindle-shaped crystalloid
bodies near the nucleus
(crystalloids of CharcotBöttcher)
•
Sertoli cells have tight
junctions that separate the
tubules into 2 compartments.
•
Adluminal compartment
containing the haploid
spermatocytes & spermatids.
•
Basal compartment
containing the diploid
spermatogonia.
•
Prevents immune attack
against sperm cells.
•
Zonulae occludens join
adjacent Sertoli cells &
form a blood testis barrier.
Sertoli cells have multiple functions including:
• Secretion of factors which regulate spermatogenesis and
Spermiogenesis- Androgen Binding Protiein( ABP)
• Secretion of inhibin which regulates hormone production
• Secretion of tubular fluid
• Phagocytosis of discarded spermatid cytoplasm
• Forms blood testis barrier
Figure 22–13.
Hypophyseal control of
male reproduction.
Luteinizing hormone (LH)
acts on the Leydig cells,
and follicle-stimulating
hormone (FSH) acts on
the seminiferous tubules.
A testicular hormone,
inhibin, inhibits FSH
secretion in the pituitary.
ABP, androgen-binding
protein. (Modified and
reproduced, with
permission, from Bloom
W, Fawcett DW: A
Textbook of Histology,
10th ed. Saunders,
1975.)
Spermatogenesis1) Spermatogonial Phase
• refers to mitotic division of the spermatogonia to provide a
continuous supply of cells that will give rise to
primary spermatocytes.
2)Meiosis
• are two successive meiotic divisions that reduce the
chromosome number from diploid to haploid and produce
spermatids.
3) Spermiogenesis
• is cytodifferentiation and transformation of spermatids to
form spermatozoa.
Spermatogonial Phase & Meiosis
Spermiogenesis
Spermatozoa
Interstitial Cells
INTRATESTTICULAR
GENITAL DUCTS
Tubuli Recti
Rete Testis
Ductuli Efferentes
Tubuli Recti
• Have a narrow lumen lined by a simple cuboidal
epithelium.
• Lead into the rete testis, a network of epitheliallined channels located in the mediastinum.
Epithelium
Rete testis
Mediastinum
testis
Connective tissue
Tubuli recti
Seminiferous
tubules
Ductuli Efferentes
• Lead from the rete testis into the epididymis.
Epithelium
Spermatozoa
Ductuli
efferentes
Connective tissue
Spermatozoa
Ductuli Efferentes
EXCRETORY
GENITAL DUCTS
• Ductus Epididymis
• Ductus Deferens (vas deferens)
•
•
Ampulla
Ejaculatory Duct
Bladder
Prostate
Menbranous urethra
Ampulla
Seminal vesticle
Urethra
Ejaculatory duct
Penis
Bulbourethral gland
Corpus cavernosum
of the penis
Ductus deferens
Ductus epididymids
Corpus cavernosum
of the urethra
Prepuce
Glands penis
Ductus efferentes
Epididymis
Testicular lobule
Tunicia albuginea
Mediastinum
testis
Tunicia vaginalis
Tubuli recti
Rete testis
Ductus Epididymis
•
•
•
•
•
begins as the terminal portions of the ductuli
efferentes fuse. Reservoir of spermatozoa.
is a narrow, highly coiled tubule, 4 to 6 meters
long.
is surrounded by connective tissue containing
blood vessels.
is subdivided into a head, body, and tail region.
its lumen is lined pseudostratified columnar
epithelium.
Epithelium
• is composed of basal and principal cells.
Basal Cells
• are round and appear undifferentiated, apparently
serving as precursors of the columnar principal
cells.
Principle Cells
• possess stereocilia (long irregular branching
microvilli) on their luminal surface.
• also possesses endoplasmic reticulum, a large
Golgi complex, lysosomes, and many pinocytotic
and coated vesicles in their apical portions
(suggesting fluid resorption).
• secrete glycerophosphocholine, a substance that
probably inhibits capacitation.
• Smooth muscle – 3 layers.
microvilli
Spermatozoa
Basal cell
Columnar cell
Connective
tissue and
smooth muscle
Figure 22–15. The highly coiled ductus epididymidis, sectioned several
times. Its wall is made of a pseudostratified columnar epithelium
surrounded by connective tissue and smooth muscle. PSH stain. Medium
magnification. Inset: Higher magnification of the epithelial cells with their
long microvilli (stereocilia).
Ductus Deferens (vas deferens)
•
begins at the end of the ductus epididymis as a
straight tube with a thick muscular wall.
Pseudostratified Epithelium
•
(with stereocilia) similar to that of the ductus
epididymis, lines the narrow, irregular lumen of the
ductus deferens.
Muscular Wall
•
is composed of inner and outer layers of
longitudinally oriented smooth muscle, separated
from one another by a middle circular layer.
Figure 22—16. Section of
the ductus deferens
showing the mucosa
formed by pseudostratified
columnar epithelium with
stereocilia and a lamina
propria. The thick outer
wall is formed of smooth
muscle (brown) and
collagen fibers (blue).
Trichrome stain. Low
magnification.
Mucosa
Inner Longitudinal
smooth muscle
layer
Circular
smooth muscle layer
Outer Longitudinal
smooth muscle layer
lumen
Epithelium
Stereocillia
Inner longitudional
muscle layer
Epithelium
Middle circular
muscle Layer
Outer longitudional
muscle layer
Seminal Vesicles
• are the paired tortuous tubular glands (15 cm in length)
located adjacent the posterior aspect of the bladder.
• their ducts join the ductus deferens just prior to its
entering the prostate gland.
Psuedostratified Columnar Epithelium
– lines the extensively folded mucosa of this gland.
– consists of low columnar cells interspersed with
cuboidal basal cells (whose height is testosterone
dependent).
Columnar Cells
– have many yellow lipochrome pigment granules and
secretory granules, contain a large Golgi apparatus, many
mitochondria, and an abundant rough endoplasmic
reticulum.
Lamina Propria
– consists of fibroelastic connective tissue surrounded by an
inner circular and an outer longitudinal layer of smooth
muscle.
Adventitia
– is also composed of fibroelastic connective tissue.
Secretory Product
• is a yellow, viscous fluid that is rich in fructose and
other substances and constitutes about 70% of the
human ejaculate.
Prostate Gland
• surrounds the urethra as it exits the urinary bladder
and is the largest accessory gland.
• consist of 30 to 50 discrete branched tubuloalveolar
glands that empty their contents into the prostatic
urethra (via excretory ducts).
Glands of the Prostate
– are arranged in three concentric layers (central,
transitional, peripheral) around the urethra and are
surrounded by a fibroelastic capsule that contains smooth
muscle.
– stroma from the capsule penetrate the gland and divide it
into lobes.
Simple or Pseudostratified Columnar Epithelium
– lines the glands, and the fibroelastic connective tissue
enveloping them contains elastic fibers and is richly
vascularized.
Epithelial Cells
– contain abundant rough endoplasmic reticulum, a welldeveloped large Golgi complex, numerous lysosomes, and
many secretory granules.
Prostatic Concretions
• composed of glycoprotein are sometimes
observed in the lumina of the glands.
• may become calcified and their numbers
increase with age.
Secretion
• of the prostate, under the influence of
dihydrotestosterone, is a whitish, thin fluid
containing proteolytic enzymes, citric acid, acid
phosphatase, and lipids.
Peripheral zone
Transition zone
Central zone
Prostatic urethra
Figure 22—18. Section of prostate showing the distribution of its glands
in 3 zones. The gland ducts open into the urethra.
Blood vessel
Basal cell
Prostatic concretion
Columnar cell
Penis
• functions both as an excretory organ for urine and as
a copulatory organ for delivering sperm into the
female reproductive tract.
• is composed of three cylindrical masses of erectile
tissue. The paired corpora cavernosa lie dorsally and
the single corpus spongiosum contains the penile
(spongy) urethra.
• is covered by skin that overlies a loose connective
tissue sheath that surrounds the corpora cavernosa
and corpus spongiosum.
• skin (distally) lacks hair follicles and contains
only a few sweat glands.
• hypodermis contains a prominent layer of smooth
muscle but no adipose tissue.
Prepuce
• that portion of skin that covers the glans penis.
• resembles as mucous membrane, since it is lined
by stratified squamous nonkeratininzed epithelium.
Tunica Albuginea
• is the thick fibrous connective tissue sheath
surrounding the three erectile bodies.
• The arrangement of the dense collagen bundles in
the tunica permit extensibility of the penis during
erection.
Corpora Cavernosa
• are the two-paired erectile bodies dorsally in the
penis.
• contain irregular vascular spaces lined by a
continuous layer of endothelial cells separated
from each other by trabeculae of connective tissue
and smooth muscle cells.
Vascular Spaces
• are decreased in size toward the periphery of the
corpora.
• become engorged with blood during erection,
making the penis turgid.
Corpus Spongiosum
• is the singular erectile body surrounding the
spongy urethra.
• its erectile tissue is similar to those of the corpora
cavernosa, except that the trabeculae contain more
elastic fibers and only a few smooth muscle cells.
• its vascular spaces are uniform throughout.
Glands of Littre
• are mucus secreting glands that are also present
throughout the length of the penile urethra.
Bladder
Prostate
Menbranous urethra
Ampulla
Seminal vesticle
Urethra
Ejaculatory duct
Penis
Bulbourethral gland
Corpus cavernosum
of the penis
Ductus deferens
Ductus epididymids
Corpus cavernosum
of the urethra
Prepuce
Glands penis
Ductus efferentes
Epididymis
Testicular lobule
Tunicia albuginea
Mediastinum
testis
Tunicia vaginalis
Tubuli recti
Rete testis
Glans Penis
• is the terminal end of the corpus spongiosum.
• contains dense connective tissue and longitudinal
muscle fibers.
Erection
• occurs when the erectile tissues become distended
with blood due to parasympathetic stimulation
mediated by tactile or erotic stimulation.
• Figure 22—21. Transverse section of the penis.
Urethra
Epithelium
Connective tissue
Glands of littre´
Blood vessel
Erectile tissue