Repro #19
Tues, 4/01/2003, 11am
Dr. Cammarata
Saira Momin
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Checked by Dr. Cammarata
Male Reproductive Histology II
Hormonal control of male reproductive function
--The structure and endocrine function of the interstitial cells are
controlled by LH (also from gonadotroph).
--Testosterone (in adenohypophysis and hypothalamus) is required to
maintain spermatogenesis. It therefore, exerts a positive control on
Sertoli (and germ) cells. Excessive testosterone acts as a feedback
inhibitor to regulate LH production and secretion by acting on the
pituitary gland and hypothalamus.
--The primary target cell for FSH is the Sertoli cell, stimulating protein
synthesis (FSH is from gonadotroph in anterior pituitary; also makes
LH)
--Sertoli cells respond to FSH by secreting androgen binding protein
(to bind testosterone in system, keeping it active)
--Inhibin is a feedback inhibitor (to gonadotroph) which regulates FSH
secretion from the pituitary gland.
-GnRH is secreted from the hypothalamus and activates the
Gonadotrophs in the pituitary
-believed sertoli feedback on Leydig cells, unclear as to why
I. Male Genital Ducts
Route of sperm from the lumen of S.T.(not on its own motility; must mature at
the epididymis) to mediastina to efferent ductules to vas deferens (penetrate
prostate) and empties through urethra (prostate gland encircles urethra)
A. Tubuli Recti (i.e. straight tubule)
1. At the apex of each lobule, the component seminiferous tubules join to
form a straight tubule
2. Each short tubule is straight, short and devoid of convolutions
3. At the junction of the seminiferous tubule the spermatogenic cells
disappear and only Sertoli cells remain
a. these form a simple columnar epithelium to cuboidal
b. epithelial cells rests on a basal lamina surrounded by loose
connective tissue, devoid of smooth muscle cells
(late spermatid to lumen of S.T. at rete testis)
B. Rete Testis
1. The straight tubules course to the dense connective tissue of the
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mediastinum where they enter a network of anastomosing
channels the rete testis
2. Appear as irregular spaces lined by simple cuboidal epithelium to
Low columnar
3. Passage of spermatozoa through the tubuli recti and the rete testis is
rapid, since in sections spermatozoa are only rarely seen
C. Ductuli Efferentes (efferent ductules) - leave testis in tunica albuginea
(look for hill, bump, scallops)
1. In the superior portion of the posterior border of the testis some 10-15
spirally wound ductules arise from the rete testis and emerge on the
surface of the testis
2. Ductules are bound by connective tissue and each is surrounded by a
thin layer of circularly arranged smooth muscle fibers
a. each ductule is 6-8 cm long and 0.05 mm in diameter
3. Lined mostly by a simple columnar epithelium which rests on thin
basal lamina
a. lumen of the ductule is irregular in outline owing to the varying
height of the epithelial cell
b. groups of tall columnar cells alternate with groups of much shorter
cells
c. many of the taller columnar cells have motile cilia which beat
helping to transport spermatozoa to the epididymis
d. non-ciliated shorter cells appear to be absorptive resorbs fluid
at S.T. and therefore pulls sperm with it from S.T. to efferent
ductules
D. Ductus Epididymides
(look for defined boundary around the circular lumen)
-10-12 efferent ductules merge into the epididymis
- head, midsection, tail
1. This duct is surrounded by connective tissue and is highly tortuous
2. Lined with a pseudostratified epithelium (ciliated columnar cells)
(has stereocilia which is made up of microtubules for resorption,
therefore not true cilia which is for motility)
a. tall columnar cells or principal cells
(i) in the caput they are very tall but gradually become lower in
successive segments and may be cuboidal in the cauda
(ii) surface of these cells contains a tuft of very long, non-motile,
stereocilia
b. basal Cells: small round or pyramidal elements lodged between the
bases of the columnar cells
(i) Function is obscure
3. Smooth muscle surrounding the epididymis increases gradually from
caput to the cauda
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a. distal part of the cauda has three-layered muscle coat
(epididymis has more smooth muscle surrounding it than efferent
ductules)
4. Functions of epididymis
a. resorption of fluids; over 90% of the fluid leaving the testis is
reabsorbed in the efferent ductules and epididymis
b. site of maturation of sperm (late spermatid becomes mature
sperm; sperm cells achieve motility in epididymis)
c. site of storage of sperm (especially cauda)
d. site of phagocytosis of defective sperm (epididymis cells
recognize destroy defective sperm to decrease birth defects)
e. secretion
E. Ductus Deferens (looks like the ureter but ureter has transitional epith.)
1. The epididymis straightens out at its termination and becomes
continuous with the ductus deferens which continues to the prostate
urethra
2. Ascends from the scrotum through the "spermatic cord" toward the
urethra
a. prior to its termination the duct dilates and enlarges into the ampulla
3. Epithelium is pseudostratified columnar and many of the tall cells
bear stereocilia
a. delicate basal lamina; thin lamina propria with elastic fibers
b. mucosa rises into longitudinal folds; stellate pattern
4. Muscle coat is thick and is composed of three distinct layers of
smooth muscle
a. inner - thin, longitudinally arranged
b. middle - large, circularly arranged
c. outer - large, longitudinally arranged
d. fibrous adventitia surrounds the muscle coat
-Ampulla
>lumen of the duct is wider and the mucosa is much more folded
>the ampulla receives the duct of the seminal vesicle and then forms
the short ejaculatory duct (pierces the prostate) which, in turn,
empties into prostatic portion of urethra
F. Spermatic Cord
1. Enclosed by cremaster muscle
2. Cord contains
a. ductus deferens
b. spermatic artery
c. pampiniform plexus
d. nerves
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3. Countercurrent exchange may cool blood going to testes
(vas deferens has pampiniform plexus and arteries which is important
b/c blood to the testis must be cooler than rest of the body)
II.
Auxiliary Genital Glands
A. Seminal Vesicles (paired, pierce prostate also; no thick connective
tissure like rete testis and rete testis has simple cuboidal)
1.Each vesicle is a tortuous, elongated diverticulum off the ductus
deferens
a. consists of a (1) external connective tissue adventitia, (2) smooth
muscle coat, and (3) highly folded mucosa
b. secondary and tertiary folding patterns (helps carry sperm)
2.Epithelium is variable showing pseudostratified columnar to regular
columnar but may be simple columnar
a. epithelium depends upon hormonal support (i.e. testosterone)
3.It is an exocrine gland whose secretion is a major component of semen
a. contains prostaglandins, fructose, lipid, and flavins
b. fructose is energy source for spermatozoa
c. flavins - yellow pigments that fluoresce
B. Prostate provides food to ejaculatory duct to keep semen liquified
(look for calcified glycoproteins which inc. with age)
1. Surrounds the urethra at its origin from the bladder
2. It is an aggregate of 30-50 small compound
tubuloalveolar glands that drain into the prostatic
urethra
a. drained by 15-30 small excretory ducts
3. Small glands (periurethral) lie in the mucosa and these
are surrounded by submucosal glands
4. Main or principal glands line peripherally and constitute
the bulk of the gland
a. main glands are embedded in an abundant,
dense stroma which is continuous with a
fibroelastic capsule
5. Secretory alveoli and tubules are very irregular and vary
greatly in size and form
a. branch frequently and both alveoli and tubules
have wide lumina
b. no distinct basal lamina and epithelium is simple
columnar or pseudostratified
c. Cytoplasm contains numerous secretory
granules and lipid droplets
6. Secretion is a thin, colorless fluid which is slightly acid
(pH 6.5)
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a. can contain corpora amylacea; i.e.,
condensations of the secretion which may
become calcified
b. proteolytic enzymes
c. zinc, citric acid and acid phosphatase occur in
high concentrations
7. Benign nodular hyperplasia - hypertrophy of both
stroma and glandular components (occurs in the
central zone of the prostate-more immediately wrapped
around urethra; difficulty urinating; correct with surgery)
8. Carcinoma of the prostate (2nd /3rd highest cause of
male death)
a. AcPase levels in blood increase
occurs in the peripheral zone; PSA (Prostate Specific
Antigen) inc. with circulating antibodies; metastatic
plasia; should feel smooth bumps/nodules;
if hard, means potential problem arising
b. “d” class carcinoma; if at this phase, less than 5
years to live; metastatic cells have broken
through thick fibroelastic capsule
c. used to treat with orchidectomy and lots of E2
(prostate requires lots of testosterone)
C.Bulbourethral Glands or Cowper's Glands (inf. To prostate)
1. Paired bodies, lying in connective tissue behind the
membranous urethra
2. Each is a compound tubuloalveolar gland whose duct
enters the posterior portion of the membranous urethra
3. Epithelium is usually simple columnar
a. secretion is clear, viscid, and mucoid
b. probably secretion serves to lubricate urethra
III.Penis
A.Introduction
1.The penis is formed of three cylindrical bodies of cavernous or erectile
tissue
a. paired corpora cavernosa penis and the
b. unpaired corpus cavernosum urethrae (corpus
spongiosum)
(both surrounded by tunica albuginea of the testis)
B.Erectile Tissue
1.The erectile tissue of the corpora cavernosa is a vast spongelike system
of irregular vascular spaces lined by endothelium and fed by efferent
arteries and drained by efferent veins
a..in the flaccid condition the cavernous spaces contain very little blood
and appear as irregular clefts
b. in erection they become engorged with blood and become large
cavities
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2.Trabeculae separate vascular spaces
a. trabeculae contain connective tissue and smooth muscle
b. helicine arteries run into the cavernous spaces (blood goes
here and drains directly into venous spaces, fills with blood as long
as there is an arousal; when arousal is lost, anastomosis is not
maintained)
3.Each of the cavernous bodies is surrounded by a thick (1mm) resistant
fibrous capsule, the tunica albuginea
a. consists of collagenous and elastic fibrous network
4.The skin covering the penis is thin and is provided with an abundant
subcutaneous layer containing smooth muscles
5.Mechanism of erection: deep artery diverted to helicine arteries
C.Male Urethra - has 3 divisions
1. Prostatic urethra
a. surrounded by prostate
b. lined by transitional epithelium
c. receives ejaculatory ducts
2. Membranous urethra
a. short, extends from prostate to bulb of corpus spongiosum
b. lined by stratified or pseudostratified columnar epithelium
3. Penile urethra
a. Passes through corpus spongiosum
b. glands of Littre are present
c. lined by stratified or pseudostratified columnar except at fossa
navicularis where epithelium is stratified squamous
Know:
Function and visual sertoli
Germ cell line and development
Structure and conduction of sperm from S.T. to penis
Bulbourethral gland not on the practical
Know difference btwn. Rete testis and seminal vesicle of written and practical