Lecture 30: Histology of the Male Reproductive System Flashcards
What produces sperm and androgen?
What transports sperm?
Testes
epididymis, ductus deferens, ejaculatory duct, urethra
What organs specialize in semen production and sperm nutrient source?
seminal vesicle
prostate gland
bulbourethral glands
Testes
Histological features
- dense CT capsule called tunica albuginea, thick at the back (mediastinum testes)
- tunica vaginalis covering the capsule (parietal and visceral layers)
Seminiferous tubules
Epithelium?
Contains?
- highly convoluted tubules lined with seminiferous epithelium
- epithelium has sertoli and spermatogenic cells, tubules surrounded by Leydig and myoid cells
Interstitial cells of Leydig
Cellular features
- lots of MT and sER containing lipid droplets
- with myoid cells and fibroblasts
What are the features of sertoli cells?
What are the features of spermatogenic cells?
Sertoli: columnar cells with cyclops nucleus and extensive processes that surround the spermatogenic cells, they nurse the spermatogenic cells
Spermatogenic: become mature sperm, immature ones in the basal lamina with mature ones in the apical portion
What is the sertoli-sertoli cell junctional complex?
sertoli cells bound to each other to form the blood testis barrier
What is the significance of the blood testis barrier?
divides the epithelium into basal and luminal compartments
basically prevents immature sperm (diploid) from mixing with circulation (haploid) until its ready (has to get through the complex once mature)
why are Sertoli cells called “nurse cells”?
they provide nutrients and phagocytose residual bodies
Once in the luminal side, what happens to the spermatid that cross the blood testis barrier?
- start as round spermatids
- later move to apical crypts of Sertoli cells and become elongated spermatids
How are mature spermatids released from the testis to the epididymis?
Spermiation process:
Intercellular bridges separates the residual bodies from the mature spermatids > spermatids are propelled into the epididymal duct
Describe the features of sperm
Head: has acrosome cap with lots of enzymes and has flattened and elongated nucleus
Tail: Middle (has MT), principal and end piece
What is the pathway of sperm transport?
straight tubules > rete testis > efferent ductules > epididymis > ductus deferens > ejaculatory duct
Epididymis
structure
features of the epithelium?
- highly elongated/coiled duct where sperm matures (gains forward motility)
- pseudostratified columnar with principal and stem cells
What are the other features of the epididymis?
-thin circular layer of smooth muscle cells + additional inner and outer longitudinal muscle layers in the tail region (where sperm is stored)
Ductus deferens
epithelium?
Structural features?
- Pseudostratified columnar with sparse stereocilia
- has inner and outer longitudinal layers and middle circular layer, outer layer has loose CT and adipocytes
Other features of the ductus deferens?
Ampulla - dilated portion that leads to prostate glands, distal ends form the ejaculatory ducts after merging with the seminal vesicle duct
What are the accessory glands of the male tract and what are their major functions?
2 seminal vesicles, 1 prostate gland, 2 bulbourethral glands, urethral glands
major function is produce seminal fluid
Seminal vesicles
epithelium?
structural features?
Major function?
- pseudostratified columnar with external CT capsule
- also has inner and outer longitudinal smooth muscle layers
- make alkaline secretions rich in fructose and prostaglandins
Describe the structure of the prostate gland
What is its major function?
- collection of glands that are embedded in dense fibromuscular capsule
- produce Zn rich alkaline fluids that neutralizes acidic vaginal envt and nourishes sperm
How are the glands of the prostate arranged around the urethra?
- Transition zone glands surround the superior urethra
- Central zone glands surround the transition zone, surround the ejaculatory ducts
- Peripheral zone glands (majority) surround the central zone
How are the secretions of all the glands of the prostate secreted?
All glands converge and empty into the prostatic urethra (mixes with secretions from the seminal vesicles and tubules)
What are the features of the individual prostate glands?
- has simple columnar or pseudostratified epithelium
- lumen has the corpora amylacea (with glycoproteins and Ca2+ deposits)
Describe the structural features of the penis
- erectile tissues include 2 corpora cavernosa (covered with tunica albuginea)
- 1 ventrally located corpus spongiosum that surrounds the penile urethra, glans penis at distal end
*these tissues have sinuses that fill with blood
How does an erection occur?
ANS > vasodilation > blood fills the sinuses within the erectile tissues > dorsal veins press against the tunica albuginea > venous outflow blocked causing the penis to harden
