Male Histology Flashcards
Testis
production of sperm and testosterone
tunica albuginea, seminiferous tubules, interstitial tissue, mediastinum (loose connective tissue)
Tunica Albuginea
dense irregular connective tissue capsule, stratum vascularis
connective tissue septa divide testis into lobules
seminiferous tubules
contain developing germ cells
sertoli cells
peritubular myoid cells
Interstitial tissue
surrounds seminiferous tubules
leydig cells and blood vessels
Mediastinum
loose connective tissue, rete testis
seminiferous tubules
lined by stratified germinal epithelium- spermatogenic cells (developing germ cells), supporting cells= sertoli cells
each lobule contains 1-4 seminiferous tubules which are surrounded by peritubular myoid cells
interstitial tissue- located between seminiferous tubules- contain leading cells, vasculature and lymphatic channels
Vascularization
extensive vasculature surrounds the seminiferous tubules for transport of hormones and nutrients for spermatogenesis
spermatogonium
diploid (2n), development and renewal
Primary spermatocyte
diploid (2n), meiotic division I
secondary spermatocyte
haploid (1n)
meiotic division II
spermatid
early and late spermatid, spermiogenesis
spermatozoa
spermiation
development variation
can see multiple stages in seminiferous tubules
developing germ cells
need sertoli cells- support cells
Sertoli cells
extend from basal lamina to lumen of seminiferous tubules
functions:
1. provide proper microenvironment for developing sperm cells
2. synthesize inhibit and androgen binding protein (ABP)- helps bind testosterone to make available to developing leydig cells
3. phagocytize regressive spermatozoa and residual bodies
4. form a blood-testis barrier through tight junctions
Sertoli cells- blood testis barrier
immunological protection of haploid cells
sertoli cells separated into basal and adluminal compartments
sequesters haploid germ cells residing in the adluminal compartment from immune suppression
created by simultaneous formation and breakdown of tight junctions between sertoli cell cytoplasmic processes
interstitial tissue
same as adventitial tissue
Leydig cells
located in interstitial tissue of the testis
secrete testosterone under regulation of LH from the pituitary
have foamy cytoplasm due to steroid production (cholesterol esters)
also interstitial cells
straight tubules
tubuli recti
connect the convoluted seminiferous tubules to the rete testis
lined by simple cuboidal or simple squamous epithelium (species specific)
rete testis
transport of sperm from seminiferous tubules to efferent ducts
network of randomly anastomosing tubules in the mediastinum
lined by simple cuboidal or simple squamous epithelium (species specific)
Excurrent duct system
efferent ductules, ductus epididymis, ductus deferens
efferent ductules
connect the rete testis with initial segment of the epididymis
ductus epididymis
resorption of fluid and androgen binding protein
sperm maturation, sperm storage
ductus deferens
transport sperm from epididymis to ejaculatory duct (or urethra) at ejaculation
efferent ductules
transport of sperm from testis to epididymis
ciliated pseudo stratified columnar epithelium
epithelium contains cells of varying height creating a scalloped appearance
cell types= tall ciliated cells and short absorptive cells
surrounded by thin smooth muscle
ductus epididymis
site of sperm maturation and storage
sperm maturation- migration and loss of cytoplasmic droplets, acquire fertilizing capacity, acquire motility, coated with decapacitation factors
sperm storage (cauda)- adrenergic sympathetic control of smooth muscles that aid in ejaculation, immobilization of sperm
ductus epididymis cells
principal cells- pseudo stratified columnar epithelium, stereo ciliated, secretory and absorptive
basal cells, intraepithelial lymphocytes
smooth muscle- thickens towards cauda (towards tail of epididymis)
extensive vascular network surrounds the duct
ductus deferens
carrying away vessel- transports sperm from epididymis in anticipation of ejaculation
tunica mucosa- pseudo stratified or simple columnar epithelium, basal cells, some stereo cilia
tunica muscularis (thick)- 3 layers of smooth muscle
Accessory sex glands
to collectively create the seminal plasma (non-sperm portion)
ampullary glands, vesicular glands (seminal vesicle), prostate, bulbourethral gland (cowpers gland)
ejaculate
contains spermatozoa from epididymis and seminal plasma from accessory glands
ampulla and vesicular glands
converge to form ejaculatory duct or empty separately into urethra depending on species
prostate and bulbourethral galnds
empty directly into urethra
comparative accessory sex glands
boar has no ampullary glands; dog has no vesicular or bulbourethral glands
cats have neither ampullary nor vesicular glands
ampullary glands
terminal dilation of the ductus deferent just prior to converging with the urethra
branched tubuloalveolar glands, rich in glycogen and lipid droplets which are added to seminal fluid
possible site of sperm storage
present in stallion, ruminants, dog and elephant- absent in boar and cat
Vesicular glands (seminal vesicles)
paired tubuloalveolar glands located dorsoventral to the urinary bladder
pseudo stratified to simple columnar epithelium w/ sparse basal cells secrete lipids (cholesterol, triglycerides, phospholipids) and glycogen comprises 30-70% of ejaculate, depending on species
duct system arrangement
pinnate- feather like
vesicular glands
seminal vesicles, septa consists of connective tissue and smooth muscle strands
prostate gland anatomy
body of prostate surrounds the pelvic urethra
disseminate prostate is embedded in the lamina proprio/submucosa of pelvic urethra
prostate gland
mucus secreting portion
compound tubuloalveolar gland (seromucous secretion) with multiple ducts opening into the urethra
cuboidal or columnar epithelium, connective tissue capsule contains smooth muscle
secretes proteolytic enzymes, electrolytes, citric acid
15-30% of ejaculate but depends on species
prostate gland
stallion only has body, some ruminants only have disseminate portion
corpora amylacea- small prostatic concretions of unknown significance- occur with increasing age
bulbourethral (cowpers) gland
secretion of mucous like fluid that flushes and lubricates the urethra prior to ejaculation
compound tubular in boar, cat and deer
tubuloalveolar in stallion, bull and ram
absent in dogs
alveolus
a sac like dilation
bulbourethral cowpers gland epithelium
tall pale basophilic columnar epithelium with basally located nuclei
fibroelastic capsule contains variable amounts of smooth and striated muscle
comprises 1-5% of ejaculate, depending on species
penis
epidermis, tunica albuginea, corpora cavernosa, urethra, corpus spongiosum, retractor penis
epidermis
stratified squamous epithelium and underlying dermis covering surface
tunica albuginea
thick layer of dense irregular connective tissue deep to dermis
it is sometimes split into an outer layer and an inner layer that comprises the capsule of the corpus cavernosum
corpora cavernosa
paired large bodies of erectile tissue located dorsal to the urethra
the blood sinuses are lined by a squamous endothelium and surrounded by a dense connective tissue capsule rich in elastic fibers
urethra
lined by a very thin layer of transitional epithelium
corpus spongiosum
smaller, medial body of erectile tissue surrounding the urethra
often accompanied by midline artery
retractor penis
bundle of smooth muscle ventral to the urethra and corpus spongiosum (musculocavernous penis)
urethra
2 regions- pelvic urethra, penile urethra
prostatic portion from bladder to prostate
membranous portion from prostate to bulb
spongiose portion from bulb distally
mucosal folds distend during erection or urination
tunica muscularis is smooth muscle near bladder, skeletal muscle more distally
pelvic urethra
mucosa- mucous glands in horses and cats mostly transitional epithelium (similar to bladder)
longitudinal folds
submucosa- stratum cavernosum, erectile tissue containing thin walled veins, analogous to corpus spongiosum of penile urethra
muscularis- inner longitudinal/middle circular/outer longitudinal smooth muscle
striated urethral muscle replaces middle circular layer at prostate
penile urethra mucosa
mostly lined by transitional epithelium, but variable
becomes stratified squamous at the urethral opening
contains mucous glands in horses and pigs
penile urethra submucosa
corpus spongiosum- erectile vascular sinuses
penile urethra muscularis
sparse smooth muscle
Bull penis
fibroelastic
sigmoid flexure, inflate and extend
Stallion penis
musculocavernous
retractor penis muscle
Canine penis
intermediate
Os penis- bone between the urethra and the corpora cavernosa
