Male Reproductive System Histology Flashcards
What are the 5 general components of the mail reproductive system?
testis excretory ducts accessory glands penis scrotum
What is the thick layer around the testis?
tunica albuginea
What does the tunica albuginea form on the inside of the testis?
it sends in projections that separate the testis into lobules
What does the tunica albuginea thicken to form on the posterior side of the testis?
the mediastinum of the testis
What is the tunica vaginalis?
it’s a protrusion of the peritonenum that forms a sac surrounding the anterior and lateral parts of the testis
What are the two layers of the tunica vaginalis?
the visceral layer is attached to the tiunica albuginea
the parietal layer is attached to the scrotum
in between is a potential space with a small amount of fluid
What is located in the lobules of the testis?
seminiferous tubules and the interstitial connective tissue between the tubules
What type of epithleium is in the seminiferous tubules? What cells make up the epithelium?
complex stratified epithelium in 4-8 layers
made up of the sertoli cells and the germ cells
Describe how you can differentiate a sertoli cell from the germ cells on histology?
the nucleus is pretty characteristics
elongated, lighter staining nucleus with a dark nucleolus
What germ cells will be located immediately adjacent to the basement membrane?
the spermatogonia
What will be the next germ cells up be?
the primary spermatocytes
What will the next germ cells up be?
the permatids
note that the secondary spermatocytes do not show up on histology typically
What will the next germ cells be?
spermatozoa
The whole process from spermatogonia to spermatozoa is called what?
spermatogenesis
The shorter process from spermatid to spermatozoa is called what?
spermiogenesis
True or false: in the male, all meiotic progeny become mature gametes
true (this is not the case in females)
Are spermatogonia diploid or haploid?
diploid
What are the three types of spermatogonia? In order of generation…
A dark
A light
B
When does maturation of the spermatogonia occur?
starting in puberty
What are the dark type A spermatogonia?
the reserve stem cells
What are the pale type A spermatogonia?
renewing stem cells
What are the type B spermatogonia?
differentiating progenitors
The primary spermatocytes win the prize for what?
they’re the largest of the germ cells
What stage of division do the primary spermatocytes enter?
meiosis 1
How long do the germ cells stay in the primary spermatocyte stage?
22+ days
How long do the germ cells stay in the secondary spermatocyte stage?
only a short amount of time
What stage of division do the secondary spermatocytes enter?
they rapidly enter meiosis II
Primary spermatocytes are __n
4n
secondary spermatocytes are __n
2n diploid
spermatids are __n
1n haploid
What’s special about how these divisions all happen?
the cells divide but remain connected by a thin strip of cytoplasm, so they basically become a synchrony of clones that form a syncytium
What are the 4 phases of spermiogenesis?
golgi phase
cap phase
acrosomal phase
maturation phase
What happens in the golgi phase?
the golgi start to form acrosomeal granules, which will begin to coalesce
axoneme assembly is initiated to start formation of the flagella
What happens in the cap phase?
the acrosomal granules fuse to form acrosomal vesicle
acrosomal vesicle forms cap over spermatid nucleus
acrosome acquires necessary enzymatic content
What happens in the acrosomal phase?
the head of the spermatid orients towards the base of the seminiferous tubule
nuclear elongation
mitochondria aggregate to the middle portion
the axonemal assembly continues to develop
What helps the nucleus elongate?
the manchette - a cylinder of numerous parallel microtubulesthat surround the nucleus just posterior to the cap
What happens in the maturation phase of spermiogenesis?
the residual body is shed
the speratozoa is released into the seminiferous tubule lumen
What happens to the residual body after it is shed?
the sertoli cell phagocytoses it
How do sertoli cells form the blood-testis barrier?
they have zonula occludens that divide the cell into basal and adluminal compartments
this forms a barrier to large molecules in the blood
Why is this blood-testis barrier so important?
As soon as the germ cells undergo meiosis I, they essentially become non-self, so it’s improtant to protect them from antibodies circulating in the blood
Where does germ cell migration occur in relation to the serotoli cells?
occurs between them
B spermatogonia traverse what as they enter meiosis I?
the zonula occludens of the sertoli cells
What hormone activates receptors on the sertoli cells?
FSH from the anterior pituitary
What will the sertoli cells produce in response to FSH activation?
androgen binding protein and inhibin
What does androgen binding protein do?
what the name says….
they bind testosterone and allow concentrations to rise in the sertoli cells - allows for normal spermatogenesis
What does inhibin do?
It feeds back to inhibit the anterior pituitary release ofFSH
What are some other functions of the sertoli cells besides these products?
- provide nutriion for the germ cells
- transports the germ cells tward te lumen
- phagocytosis of residual bodies
- production and regulation of some testicular fluid
What is located between the seminiferous tubules?
the interstitial tissue
includes collagenous fibers, blood vessels, lymph, nerves, fibroblasts, macropahges, mast cells, undiffererntiated mesenchymal cells, and…
interstitial cells of leydig
Describe interstitial cells of leydig.
they occur in compact groups
they’re large and eosinophilic with large, round nuclei
extensive smooth ER
lie near non-fenestrated blood or lymph capillaries
have crystalloi dinclusions called reinke crystals
What so interstitial cells lf leydig do?
produce testosterone
What hormone will activate receptors on the Leydig cells to promote testosteron production?
LH or ICSH in males
What will the LH do in terms of negative inhibition?
it will inhibit the hypothalamic release of GnRH, which thus decreases further LH release
True or false: Leydig cells are temperature sensitive, so won’t produce testosterone if too hot.
false - they are not temperature sensitive
What are the excretory ducts of the testis in order?
tubuli recti (straight tubules) rete testis ductuli efferentes (efferent ductules) Ductus epididymidis (epididymis9 Ductus (vas) deferens
Describe the tubuli recti (straight tubules). What do they do?
They’re very short tubes that connect the seminiferous tubules to the rete testis in the mediastrinum
the epithelium is simple columnar (cells are sertoli-like)
easiest to identify based on location next to the reti testis
Describe the rete testis.
it’s a labyrinthine plexus of epithelially-lined channels in the mediastinum of the testis
Describe the epithelium of the rete testis.
simple cuboidal
What part of the tubules emerge from the mediastinum on the posterior-superior aspect of testis?
the efferent ductules
Describe the efferent ductules
each tubule forms a conical spiral with the apex towards the mediastinum.
they get wider as you continue up
have smooth muscle and elastic fibers
How many efferent ductules are there per testis usualy?
12
Describe the epithelium of the efferent ductules?
simple columnar epithelium that varies by height
some are tall cells with cilia
others are short cells with microvilli
What receives the contents of the efferent ductules?
the epididymis
Describe the epididymis
It’s a set of highly convoluted ducts (5-7 meters long!)
What happens in the epididymis
further sperm maturation
they think the sperm gains various factors that incapacitate it here - then once it’s in the female reproductive tract, those factors are removed and the sperm is free to do what it wants
Describe the epithelium of the epididymis.
it’s pseudostratified columnar with stereocilia and a distinct basement membrane
What do those stereocilia do?
they have both absorptive and secretory activities
What is arranged around the tubules of the epididymis?
circularly arranged smooth muscle
What does the epididymis feed into?
the vas deferens
Describe the vas deferens
it’s just a tube with a very thick muscular wall
it runs with the spermatic cord, arteries, beins, lymph vessels, nerves and cremaster muscle in the srotum
Describe the epithelium of the vas deferens.
it’s still pseudostratified columnar epithelium with stereocilia and a basement membrane
What is just outside of the basement membrane in the vas deferens?
a small layer of fibroelastic lamina propria
What is special about the luminal side of the vas deferens?
it has a lot of luminal folds - gives it a stellate appearance almost
What are the three distinct layers of smooth muscle in the vas deferens?
inner longitudinal
middle circular
outer longitudinal
(then there’s an adventitia)
What do we call the terminal dilation of the vas deferens?
the ampulla
Describe the ampulla?
it’s a dilated area where the mucosa is highly folded
musculature is less regularly arranged
no stereocilia on the epithelium anymore
What are the three accessory glands of this system?
seminal vesicles
prostate gland
bulbourethral glands
Describe the seminal vesicles
unbranched tubular diverticulum of the distal end of the vas deferens
When does the seminal vesicles fully develop?
not until puberty
Describe the mucosa of the seminal vesicles? Epithelium?
it’s an intricate system of folds (primary, secondary and tertiary) that create numerous cavities of varying sizes - usually are connected to an inner main channel
the epithelium is typically columnar
What do the epithelial cells sometimes contain in the seminal vesicles?
secretory vesicles and clumps of a yellowish lipochrome pigment
Describe the seminal vesicles muscularis?
has an internal circular and oblique smooth msucle layer
then an external longtudinal layer
What is the function of the seminal vesicles?
secrete a slightly yellow, viscous fluid rich in fructose, ascorbic acid and prostaglandins
What is the purpose of the fructose?
energy source for the motile sperm
Describe the type of gland the prostate is
it’s a compound tubuloalveolar gland
About how many glands surround the prostatic portion of the urethra?
About how many actually open into the prostatic urethra?
30-50
16-32
Describe the capsule of the prostate gland?
it’s fibroelastic tisuse with an inner portion that is rich in smooth muscle
Describe the stroma of the prostate gland
about 1/4 of the gland - dense fibro-muscular tissue rich in collagen, elastin and smooth muscle fibers
What are the three groups of glands that make up the prostate gland?
the mucosal
submucosal
main
Which grlands are located in the periurethral tissue and grow too big in BPH?
the mucosal glands
What glands are the outer and largest portion of the gland to provide the bulk of the secretions?
the main glands
Describe the eptihelium of the prostate.
it’s highly folded simple cuoboidal to columnar
the cells will contain secretory vesicles and yellowish lipoidal droplets
What’s the giveaway that your’e looking at prostate on histology?
Concretion in the alveoli
made of calcified proteins and carbohydrate - may appear lamellated (first appears in adults, increases with age)
What is the function of the prostate gland?
makes a thin, milky, faintly acid fluid that contains citric acid, lipid, diastase, proteolytic enzymes, beta glucuronidase
About what portion of seminal fluid is comprised or prostatic secretion?
about 25%
When doe the prostate make it’s secretion
continuously, but especially during coitus
What marker do we use for prostatic secretion?
PSA
also contains PAP
Where are the bulbourethral glands located?
they lie in the connective tissue behind the membranos urethra
What do the bulbourethral glands do?
secrete a clear viscous lubricating material into the urethra under conditions of sexual excitement
Describe the skin of the penis
it’s thin without fat
has tall papillae and elastic loose connective tissue
note the prepuce is a circular fold of skin covering th e glans
What are the three cylindical bodies of erectile tiusse in the penis?
two corpora cavernosa dorsally
corpus spongiosum ventrally
Describe the structure of the cavernous bodies?
made of irregular vascular spaces that form a trabecular-like network - lined with endothelium
What happens to these vascular spaces when the penis is in a flaccid state?
tend to collapse
What vessels run longitudinally through the corpora cavernosae?
deep arteries
What vessels to the deep arteries give rise to?
helicine arteries
Describe these helicine arteries?
they spiral in a flaccid penis
have a thick tunic amedia and the intima has longitudinal ridges with smooth muscle that occlude the lumen when there is muscle tone (erection)
they open into the cavernous spaces to fill the region during erection
Where are the venules located in the penis?
on the inner surface of the tunica albuginea
What do the venules drain?
the cavernous spaces
What do the venules pierce the tunica albuginea to unite/
the deep dorsal vein of the penis
Describe what happens during erectil?
- parasympathetic stimulation
- smooth muscle of supplying arteries relax and vessels dilate
- the lumina dilate
- venules become comrpessed
- venous drainage reduced
- corpora cavernosa become trugid with blood
What happens in emission?
- sympathetic activity
- the smooth muscle coat of the epididymis, vas deference and ejactulatory duct contract
- peristaltic contractions propel sperm intot he urethra
- the smooth muscle in seminal vesicles and prostate contracts such that seminal and prostatic fluids join the sperm
What are the three sections of the male urethra
prostratic
membranous
penile
Desribe the epithelium of the prostatic urethra?
transitional to striatied columnar epithelium
Describe the epithelium of the membranous urethra?
stratified columnar epithelium
Describe the epithelium of the penile uretrha?
stratified columnar to stratified squamous non-keratinizing distally
Describe the skin of the scrotum
thin
fair amount of melanin
dermis with sebaceous galnds, sweat glands and hair follicles
no fat in the subcutneous tissue
What is the thick layer of smooth muscle in the scrotum?
dartos muscle
Describe how the scrotum can act as a thermoregulator?
cold: dartos muscle contracts to pull the testis close to body
warm: dartos muscle relaxes and testis descend
What’s the giveaway that your’e looking at prostate on histology?
Concretion in the alveoli
made of calcified proteins and carbohydrate - may appear lamellated (first appears in adults, increases with age)
What is the function of the prostate gland?
makes a thin, milky, faintly acid fluid that contains citric acid, lipid, diastase, proteolytic enzymes, beta glucuronidase
About what portion of seminal fluid is comprised or prostatic secretion?
about 25%
When doe the prostate make it’s secretion
continuously, but especially during coitus
What marker do we use for prostatic secretion?
PSA
also contains PAP
Where are the bulbourethral glands located?
they lie in the connective tissue behind the membranos urethra
What do the bulbourethral glands do?
secrete a clear viscous lubricating material into the urethra under conditions of sexual excitement
Describe the skin of the penis
it’s thin without fat
has tall papillae and elastic loose connective tissue
note the prepuce is a circular fold of skin covering th e glans
What are the three cylindical bodies of erectile tiusse in the penis?
two corpora cavernosa dorsally
corpus spongiosum ventrally
Describe the structure of the cavernous bodies?
made of irregular vascular spaces that form a trabecular-like network - lined with endothelium
What happens to these vascular spaces when the penis is in a flaccid state?
tend to collapse
What vessels run longitudinally through the corpora cavernosae?
deep arteries
What vessels to the deep arteries give rise to?
helicine arteries
Describe these helicine arteries?
they spiral in a flaccid penis
have a thick tunic amedia and the intima has longitudinal ridges with smooth muscle that occlude the lumen when there is muscle tone (erection)
they open into the cavernous spaces to fill the region during erection
Where are the venules located in the penis?
on the inner surface of the tunica albuginea
What do the venules drain?
the cavernous spaces
What do the venules pierce the tunica albuginea to unite/
the deep dorsal vein of the penis
Describe what happens during erectil?
- parasympathetic stimulation
- smooth muscle of supplying arteries relax and vessels dilate
- the lumina dilate
- venules become comrpessed
- venous drainage reduced
- corpora cavernosa become trugid with blood
What happens in emission?
- sympathetic activity
- the smooth muscle coat of the epididymis, vas deference and ejactulatory duct contract
- peristaltic contractions propel sperm intot he urethra
- the smooth muscle in seminal vesicles and prostate contracts such that seminal and prostatic fluids join the sperm
What are the three sections of the male urethra
prostratic
membranous
penile
Desribe the epithelium of the prostatic urethra?
transitional to striatied columnar epithelium
Describe the epithelium of the membranous urethra?
stratified columnar epithelium
Describe the epithelium of the penile uretrha?
stratified columnar to stratified squamous non-keratinizing distally
Describe the skin of the scrotum
thin
fair amount of melanin
dermis with sebaceous galnds, sweat glands and hair follicles
no fat in the subcutneous tissue
What is the thick layer of smooth muscle in the scrotum?
dartos muscle
Describe how the scrotum can act as a thermoregulator?
cold: dartos muscle contracts to pull the testis close to body
warm: dartos muscle relaxes and testis descend
