Editing Testicle (section)

== Microanatomic architecture ==

* '''Comprised of (2):'''
** '''Seminiferous tubules'''
** '''Interstitial tissue'''
* '''Seminiferous tubules''' (seminal vesicle lobules in above diagram)
** '''Contain Spermatogenic cells and supporting cells, including Sertoli cells'''
*** '''Spermatogenic cells'''
**** '''Comprise the bulk of the testicular volume'''
*** '''Sertoli cells'''
**** Rest on the tubular basement membrane
**** '''Support spermatogenesis'''
**** '''Secrete Inhibin which inhibits FSH secretion'''
**** '''Tight junctions between Sertoli cells provide an intracellular barrier, known as the blood-testis barrier,''' that allows for spermatogenesis to occur in an immune privileged site
***** This forms a high-resistance barrier that prevents the deep penetration of most drugs, molecules, and electron-opaque tracers into the seminiferous epithelium from the testicular interstitium.
***** '''Sertoli cell tight junctions also segregate pre-meiotic germ cells (spermatogonia) from meiotic and post-meiotic germ cells.'''
***** '''The blood-testis barrier develops during puberty'''
****** '''Clinical implication: since post-meiotic germ cells only exist after puberty, testicular insult (biopsy, torsion, trauma) before puberty will not induce anti-sperm antibodies'''
** '''The convoluted seminiferous tubules become straight at their apices and then enter the mediastinum testis to form an anastomosing network of tubules, called the rete testis. The rete testis form 12-20 efferent ductules that anastamose with in head of the epididymis'''
** '''Structures the sperm passes through in sequence: seminiferous tubules-->straight tubules (tubuli recti)-->rete testis-->efferent ductules-->head, body, tail of epididymis-->vas deferens-->ejaculatory duct-->prostatic urethra'''
** '''Interstitial tissue'''
*** '''Around the seminiferous tubules'''
*** '''Makes up to 20-30% of the testicular volume'''
*** '''Contains Leydig cells, mast cells, macrophages, nerves, blood vessels, and lymphatic vessels'''
*** '''Leydig cells'''
**** '''Produce testosterone and activin'''
***** '''Activin stimulates production of FSH'''