Male Reproductive System

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Male Reproductive System
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Testis functionally a double gland Exocrine
Cytogenic gland sperm Endocrine Testosterone
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Ovoid Gland (1.8 incles long) Thick capsule (
Tunica Albuginea) Fibro-elastic tissue (white
when fresh) Inner layer is the Tunica
vasculosa Capsule projects inward along
posterior margin (mediasinum testis)
hilus Thin fibrous septulae radiate from
mediastinum to capsule incomplete
branching form pyramidal compartments (lobuli
testis) 250 lobuli apex toward mediastinum
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Highly contorted Seminiferous tubules occupy
compartments Tubules surrounded by layered
fibrous sheath local condensation of
C.T. Bed of loose C.T. with interstitial cells
of Leydig Leydig cells large, in
groups C.T. stroma (loose soft tissue)
between seminiferous tubules
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Seminiferous tubules 1 to 4 per lobule Each
tubule 1 3 feet long 0.2 mm. wide Lined with
specialized, stratified cuboidal epithelium
(germinal epithelium) Basement membrane Central
canal (lumen) appears at puberty At apex of
lobule tubule loses convolutions becomes
straight tubulus rectus Atrophy begins 3rd
decade of life
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Sertoli Cells (Sustentacular Cells) Supporting/Nut
ritive cells Few spaced regularly Base on
basement membrane Free end extends to lumen Sex
cells crowded between indent sides of Sertoli
Cells Nucleus above but near base of cell
prominent nucleolus
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Spermatids remain attached during maturation
period spermiogenesis Germ cells (sex cells)
stratified layer 4 to 8 cells
deep Differentiate progressively periphery
toward lumen Sequence of differentiation
spermatogenesis - not every stage is seen at any
level Human takes 2 to 3 weeks
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Spermatids Product of secondary
spermatocytes Haploid Secondary
Spermatocytes Undergoes 2nd meiotic
division Sister chromatids separate Primary
Spermatocytes Replication of DNA each
chromosome composed of sister chromatids Largest
cell Undergoes 1st meiotic division reduction
division Spermatogonia Near basement
membrane Ordinary mitotic division to produce
additional spermatogonia Begins as diploid cell
1N
2N DNA 1N - chrsms
4N DNA
2N
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Spermatogenesis Spermatogonia ? Primary
Spermatocyte ? Secondary Spermatocyte ?
Spermatid Spermiogenesis Spermatid ? Mature Sperm
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Spermatogonia reserve cells male can produce
sperm throughout life production tapers off with
age Pool of cells to draw from for
spermatogenesis Primary Spermatocytes largest
cells dark staining nuclei (largest amount of
DNA) Secondary Spermatocytes half volume of
primary immediatedly undergo second meiotic
division, hence are rarely seen in
sections Spermatid half volume of secondary
amount of DNA halved, hence nucleus lighter
staining and smaller undergoes spermiogenesis ?
lose much of cytoplasm, form flagellum, form
acrosome
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Testis contained in scrotal sac specialized
integument Epidermis changeably thick more
pigmented Dermis sparse hair follicles large
sebaceous glands Subcutaneous tissue thick
layer of smooth muscle (dartos tunic) fat cells
absent Twin cavities (invasion of two peritoneal
sacs tunica vaginalis) push into
subcutaneous tissue late fetal life parietal
layer lines scrotal sac visceral layer covers ¾
testis epididymis surface mesothelium
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Male Genital Ducts (seven structural levels along
course) Tubuli Recti apex of a lobule
seminiferous tubules become single, short,
straight tube diameter 25 µ only Sertoli cells
remain simple epithelium (cells columnar or
cuboidal)
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Male Genital Ducts (seven structural levels along
course) Rete Testis Tubuli recti open into
network of canals (in mediastinum) Rete
Testis irregular anastomosing channels
variable width Lining simple cuboidal to
simple columnar some cells with single
flagellum
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Ductuli Efferentes 10 15 efferent
ductules Emerge from rete testis upper
part each 3 inches long width 0.2 to 0.4
mm. spirally wound lobule of epididymis (conical
shape) several lobules ? head of the
epididymis Epithelium simple columnar, some
taller cells are ciliated shorter cells form
intra-epithelial glands distinct basement
membrane Near end change to epithelium of
epididymis
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Ductus Epididymis Compact mass along posterior
side of testis Middle lower regions body
tail (single coiled duct) Highly tortuous duct
(20 feet long) 0.4 mm. wide Epithelium
pseudostratified with basal cells tall
columnar cells Basal cells contain fatty
droplets Tall cells secretion droplets,
granules, vacuoles, pigment Surface pencil
of nonmotile, clumped cilia (stereocilia)
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Ductus Deferens Duct of Epididymis enlarges into
Ductus Deferens Tube straightens traverses
inguinal canal behind peritoneum toward
urethra 18 inches long 2 to 3 mm. wide Wall
very thick lumen relatively narrow! Mucosa of
Ductus Deferens Epithelium pseudostratified
many tall cells with stereocilia delicate
basement membrane lamina propria many elastic
fibers 4 to 6 longitudinal folds (stellate
lumen, c.s.)
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Ductus Deferens Submucosa indefinite at
best deeper layers of lamina propria ? blood
vessels Muscularis very heavy give duct
cord-like feel thickest in pelvic
portion inner layer relatively thin middle,
circular layer strongly developed loosely
arranged longitudinal bundles mingle outer
layer also robust Adventitia fibrous
typical blends with adjoining tissues
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Inner longitudinal
Lamina Propria
Epithelium
Circular
Muscularis
Outer longitudinal
Adventitia
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Terminal end expands into ampulla Lumen
larger Mucosa more folded Branch
anastomose Outpocketings invade
muscularis Muscularis considerable interlacing
of circular longitudinal bundles
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Ejaculatory Duct Short (0.8 inches) slender,
terminal segment Appears formed by union of
ampulla seminal vesicle Pierces prostate
gland Highly folded mucosa (like
ampulla) Epithelium columnar to
pseudostratified appears secretory Supporting
wall fibrous tissue only Terminal part
cavernous vascular spaces (like urethra)
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Glands of the Male Reproductive Tract Seminal
Vesicle a diverticulum off ductus
deferens Convoluted, glandular sac (2 inches
long 0.7 inches wide) Lumen irregular
highly recessed with side bays Some mammals lack
seminal vesicles Mucosa remarkably folded
(intricately) Primary folds ? secondary folds ?
tertiary folds Large lumen with stored
secretion Secretion yellowish gelatinous
sticky mucoid weakly alkaline
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Seminal vesicle Epithelium pseudostratified
(some areas simple columnar) Lamina Propria
thin layer richly elastic C.T. no
recognizable basement membrane Muscularis less
heavy than ductus deferens internally
circular oblique bundles smooth muscle -
interlace externally longitudinal layer
smooth muscle Adventitia thin, largely elastic
fibers blends to surrounding tissue Many
blood vessels autonomic ganglia
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Prostate Gland 1.5 inches in diameter, surrounds
urethra (at junction with urinary
bladder) Aggregate of 30 to 50 tubulo-alveolar
glands 5 lobes Empties into prostatic urethre
via 15 30 ducts Capsule Stroma
fibro-elastic inner zone peculiar rich in
smooth muscle Abundant dense stroma embeds
alveoli septum-like bands join capsule
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Prostate Gland Parenchyma elongate alveoli
tubules vary greatly in size
shape Epithelium markedly folded (large
small folds) cells cuboidal to
columnar cells contain secretory
granules Ducts irregular lumen (resemble
secretory tubules) Terminal excretory
ducts pseudostratified with patches of
secretory cells Secretion frequent ovoid
prostatic concretions (corpora amylacea)
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Note irregular shape and variable size of
glandular alveoli. Lining epithelium is folded
and cuboidal to columnar. The glands are embedded
within the stroma, which is a fibroelastic C.T.
with numerous strands of smooth muscle.
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Note concretions in lumen Corpora Amylacea
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Bulbo-urethral Glands of Cowper Compound
tubulo-alveolar (size of a pea) special type
of urethral gland Surrounded by skeletal
muscle Thin capsule septa ? lobules Stroma
may contain smooth muscle fibers Parenchyma
secretory endpieces variable size Epithelium
variable cuboidal to columnar
pale Resemble serous alveoli
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Bulbo-urethral Glands of Cowper Secretion
clear, viscid, gairy, stringy Most lobules have
ducts ducts locally dilated Main excretory
duct patches of mucous cells (even alveoli) 3
4 cm. long open into cavernous
urethra surrounded by thin rings of smooth
muscle epithelium simple stratified columnar
near outlet
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Penis Three cylinders of erectile tissue
cavernous urethra Corpus cavernosum urethrae (c.
spongiosum) unpaired surrounds cavernous
urethra terminal elargement glans
penis Parallel dorsal the corpora cavernosa
penis united by common median partition
pectiniform plexus All cavernosa surrounded by
muscular subcutaneous tissue and thin
skin Terminally skin reduplicates
prepuce also covered by tunica albuginea
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Arrows show portions of the space between prepuce
and the glans
Corpus cavernosum urethrae
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Quiescent helicine arteries have intima thrown
into folds, cut transersely, the lumina appear
crescent shaped. (the arrows).
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