Overview Anatomy Tunica albuginea an unusually thick, dense connective tissue capsule that covers each testis Lobules incomplete connective tissue septa that projects from tunica albuginea divides each testis into lobules Seminiferous tubules lobules consist of seminiferous tubules spermatogenesis occurs in seminiferous tubules seminiferous tubule epithelium contains spermatogenic cells and Sertoli cells Spermatogenic Cells Found within the seminiferous tubules Spermatogenic cells are organized in poorly defined layers of progressive development between adjacent Sertoli cells most immature spermatogenic cells, spermatogonia, rest on basal lamina most mature spermatogenic cells, spermatids, attach to apical portion of Sertoli cells and border lumen of seminiferous tubules dividing spermatogenic cells form daughter cells that remain joined by cytoplasmic bridges Sertoli Cells Function to synthesize and secrete hormones including anti-Müllerian hormone (AMH) released during embryogenesis and inhibits development of Müllerian (paramesonephric) ducts androgen-binding protein (ABP) released into luminal space of seminiferous tubules, near developing spermatogonia ABP binds testosterone and maintains high local testosterone levels, necessary for spermatogenesis inhibin provides negative-feedback on hypothalamic-pituitary axis and inhibits GnRH, LH, and FSH has more of an effect inhibiting FSH than GnRH or LH other products other products that support developing spermatogonia and support spermatogenesis Sertoli cell junctional complexes extensive tight junctions bind adjacent Sertoli cells junctional complexes establish 2 epithelial compartments basal compartment occupies space between basal lamina and Sertoli cell - Sertoli cell junctional complexes contains spermatogonia luminal compartment occupies space above Sertoli cell - Sertoli cell junctional complexes contains primary spermatocytes, secondary spermatocytes, spermatids, and spermatozoa blood-testis barrier established by junctional complexes spermatogenic cells differ antigenically from somatic cells;therefore, a blood-testis barrier is required to prevent spermatogenic cell exposure to immune system and a resulting autoimmune response