Spermatogenesis
The mature spermatozoonLeydig cells: They are most common in the tubular interstitium, they can be found occasionally in the mediastinum of testis, epididymis or even in the spermatic cord. Leydig cells synthesize testosterone, these cells have round vesicular nuclei with one or two nucleoli. Most of leydig cells are round or polygonal in shape but some are small &spindle- shaped & those are thought to be immature form.
The Rete Testis: Is a complex channels located at the mediastinum of testis. The spermatozoon formed in the S.T loops, pass to the terminal portions & then via few short straight tubules, they reach to the rete testis, both straight tubules & rete testis are lined by simple cuboidal or low columnar epithelium bearing microvilli on their luminal surface .
Seminiferous tubul
Rete testis
The efferent ductules are lined by a mixed undulating epithelium of tall ciliated columnar cells & non ciliated cuboidal or low columnar cells
The epididymis
is lined by a tall columnar epithelium bearing very long a typical microvilli which are immotile, so they are called "stereocilia" because they do not contain the microtubules & not function like the cilia. The cells also posses lysosomes, RER &prominent Golgi.Vas deferens:
internal to the inner layer there is fibroelastic lamina propria covered by columnar epithelium similar to that of the epididymis but thrown into longitudinal folds, this produce small stellaite lumen, contraction of thick muscular wall move the spermatozoa forward.
each vas deferens has a dilatation called "ampulla" where the muscle layer become thinner &the folds are branched & taller at distal end of the ampulla, the vas deferens joined the short duct from the seminal vesicle.
Accessory genital glands 1- Seminal vesicle: S.V is a coiled tube &surrounded by an inner circular &outer longitudinal smooth muscle fibers.
The mucosa is composed of fibroelastic lamina propria covered by epithelial cells, the mucosa is thrown into tall narrow complicated folds covered by non- ciliated tall columnar epithelium & some few basal rounded cells lie at the basement membrane , the tall cells have a characteristic secretory vacuoles near their luminal surface +RER.
Penis: Is composed of erectile tissue & contains part of the urethra, the erectile tissue arranged into 2 dorsal cylinders (corpora cavernosa) + smaller central ventral cylinder (corporus spongiosum) through which the penile urethra runs. The cylinders are each surrounded by a dense fibrocollagenous sheath called (tunica albuginea) which also holds them together.