Male Reproductive Histology Flashcards
What surrounds the testes?
tunica albuginea –> tunica vaginalis = visceral and parietal layers
What is aWhat is the mediastinum testis?
thickening of tunica albuginea in the posterior
contains rete testis
What is a lobule of a testis?
seminiferous tubules + leydig cells
~250 lobules in each testis
What type of cells make up the semineferous tubules?
stratified epithelium:
sertoli cells = support cells
spermatogenic cells
surrounded by peritubular/myoid cells
What do the ends of seminiferous tubules become?
straight tubules
proximal part = sertoli cells
distal part = simple cuboidal
What is rete testis?
anastomosing channel w/in mediastinum
straight tubules continuous w/ this
*simple cuboidal/low columnar
What are efferent ductules?
connect mediastinum to epidydmis
transmit sperm from testis to epidydmis
What is contained in the head of the epidydmis?
efferent ductules
pseudostratified columnar epithelium
What is contained in the body of the epididymis?
principal cells = pseudostratified columnar epithelium w/ stereocilia
What is distinct about the lumen of the epididymis?
lumen is smooth, not folded
stereocilia on principal cells
What characterizes the ductus deferens?
long muscular tube w/ pseudostratified columnar epithelium w/ stereocilia
muscular wall (inner and outer longitudinal w/ middle circular layer)
surrounded by loose CT and fat
*folded lumen*
What is the ampula of the ductus deferens?
dilated portion leading into prostate
taller, branched mucosal folds w/ glandular diverticula
distal end receives ducts of seminal vesicles
How are spermatogenic cells arranged in seminiferous tubules?
most immature at edges near myoid cells
sperm cells in/close to lumen
(mature toward lumen)
What are type A spermatogonia?
ovoid nuclei w/ intensely basophilic, granular chromatin –> remain as reserve cells or later become type B
What are type B spermatogonia?
spherical nuclei w/ chromatin condensed into large clumps around a central nucleolus –> enter meiosis to become mature sperm
What is the sequence of spermatogenesis?
type B spermatogonia –> primary spermatocyte (2n, 4d) –> secondary spermatocyte (1n, 2d) –> spermatids (1n)
What is the golgi phase of spermiogenesis?
hydrolytic enzymes from golgi –> make acrosomal vesicle
dev next to nucleus
where acrosome goes = anterior pole of sperm
centrioles migrate to posterior pole
What is the cap phase of spermiogenesis?
acrosomal vesicle enlarges and spreads over antior 1/2 of nucleus = cap
nuclear envelope attaches to acrosomal sac
What is the acrosome phase of spermiogenesis?
spermatid orients itself so head is embedded in sertoli cell –> points toward basal lamina
manchette is formed from cytoplasmic microtubules (involved in protein trafficking)
What is the maturation phase of spermiogenesis?
excess cytoplasm removed as residual bodies creating mature spermatozoon
spermatids released into lumen of seminiferous tubule
What is the structure of a sperm head?
flattened, condensed, elongated nucleus
2/3 of nucleus covered by acrosomal cap
What is the structure of a sperm tail?
mid piece = mitochondria
principal piece = fibrous sheath, external course fibers (longest part)
end piece = containes axonemal complex (connects microtubules together)
What is the pathway of sperm?
seminiferous tubule
straight tubule
rete testis
efferent ductule
epididymal duct
ductus deferens
ejaculatory duct
what characterize sertoli cells?
support cells, don’t replicate after puberty
columnar w/ extensive apical and lateral processes surrounding spermatogenic cells
tight jxns btw cells = blood-testis barrier
secrete androgen-binding protein (ABP)
What is ABP?
androgen-binding protein
secreted by sertoli cells
binds T and DHT w/ high affinity to transport thru blood
What is the lamina propria surrounding seminiferous tubules?
layers of myoid cells that contract creating peristaltic waves to move spermatozoa through tubules to duct system
normal aging –> thickening of LP –> decreased rate of sperm production and size of seminiferous tubules
excessive thickening early in life = infertility
What is in the intertitial stroma of testes?
loose intertubular CT
blood vessels
leydig cells
WHat are crystals of reinke?
rod-shaped cytoplasmic crystals of androgens
in leydig cells
What characterizes leydig cells?
large, eosinophilic cells w/ lipid droplets
crystals of reinke
elaborate smooth ER
secrete T and INSL3
What do T and INSL3 do in embryo?
T needed form gonad dev
INSL3 –> decent of testes
What do T and INSL3 do in puberty?
T for sperm production, accessory sex gland secretion, secondary sex characteristics
INSL3 promotes meiotic divisions in seminiferous tubules
What do leydig cells do in adulthood?
T for maintenance of spermatogenesis, secondary sex char, accessory sex glands
secrete oxytocin to stim contraction of myoid cells moving sperm toward efferent ductules
What are the accessory sex glands in a male?
seminal vesicles = 2
bulbourethral glands =2
prostate
What forms the ejaculatory duct?
short excretory duct w/ ampulla of ductus deferens
What are the layers af the seminal vesicle?
mucosa = folded to increase secretory SA; pseudostratified columnar epithelium resting on basal lamina
smooth muscle = contracts during ejaculation
fibrous coat
What is the secretion from the seminal vesicles?
whitish, yellow viscous fluid = 75% of semen
contains fructose, AAs, ascorbic acid, and prostaglandins
nourish sperm
What characterize the bulbourethral glands?
paired, pea-sized glands in urogenital diaphragm
ducts that join w/ spongy urethra
compound tubuloalveolar glands = simple columnar epithelium
What is the secretion from the bulbourethral glands?
clear, mucus-like w/ galactose, sialic acid, methylpentose
main part of preseminal fluid - lubricates urethra and neutralizes any traces of acidic urine
What is the histology of the prostate?
glands lined by simple columnar or pseudostratified epithelium
What does the prostate secrete?
clear, slightly alkaline fluid to neutralize acidic environment of vagina
provides nutrients, transports, and liquefies sperm
What are the 4 zones of the prostate?
peripheral = posterior and lateral parts of gland; where prostatic carcinomas start (DRE)
transitional = surrounds prostatic urethra; BPH location
central = surrounds ejaculatory ducts (basophilic cytoplasm w/ large nuclei at diff levels in adjacent cells)
Periurethral = mucosa and submucosa (BPH grows here later)
WHat is benign prostatic hyperplasia?
primarily occurs in transitional zone –> later in periurethral zone
cells undergo extensive division –> nodular masses of epithelial cells
causes partial or total obstruction of prostatic urethra
What characterizes prostate cancer?
prostatic adenocarcinoma = MC cancer in men
70% of 70-80 yo have prostatic adenocarcinoma
arise in peripheral zone = easily felt on DRE
PSA for early diagnosis, better for tracking progress
most cases are asymptomatic until very late in disease
What is the pH of semen?
average ejaculate?
7.7
3 mL, 100 million sperm per mL, 20% abnormal, 25% immotile
What binds the 3 corpora of the penis together?
tunica albuginea
How are the corpora cavernosa supplied w/ blood?
deep artery of penis runs w/in corpora cavernosa –> branches into helicine arteries
How does bloodflow contribute to an erection?
blood fills sinuses in erectile tissue –> increased size and rigidity
sinuses anastomose w/ veins allowing blood drainage
engorgement of sinuses –> compresses and restricts venous outflow –> blood trapped in sinuses –> erection maintained
How does an erection occur?
PNS signals from pelvic splanchnic ns –> penis –> NO –> GC –> cGMP –> Ca storage in smooth muscle cells –> Sm m relaxation –> increased blood flow into sinusoids of erectile tissue
What is detumescence?
stopage of an erection
How does detumescence occur?
SNS –> contraction of SM and decreased blood flow to sinusoids –> opening of veins of penis and release of blood
Phosphodiesterase breaks down cGMP –> decreases sm m relaxation
*PDE inhibitors*
