Testis and spermatogenesis - Examine the preserved-mounted specimens of testes and vas deferens, noting the macroscopic features (lobes, tubules, etc.) for correlation with these structures on the slides.

Examine sections of the testis. Identify the capsule (tunica albuginea), interstitial tissue or stroma, and the seminiferous tubules .

Clinical note: Failure of the testes to descend into the scrotum during fetal development (cryptorchidism) maintains their temperature at 37 degrees C which inhibits spermatogenesis, although testosterone production can still occur. Excessive blood flow or dilated vasculature in the scrotum (varicocoele) is another potential cause of male infertility and can be surgically corrected.

Study a schematic diagram of spermatogenesis and its relationship to the sustentacular Sertoli cells. In a tubule cut transversely, identify myoid cells, Sertoli cells (with nucleoli), spermatogonia, and the large primary spermatocytes. The smaller secondary spermatocytes are much more short-lived and therefore more difficult to find. (Do not spend time looking for these.) Identify spermatids and differentiating spermatozoa. Try to distinguish some of the morphological stages and changes that occur in the differentiating spermatids during spermiogenesis.

Why are the secondary spermatocytes rare?

What is the longest stage of spermatogenesis?

Indicate three functions of Sertoli cells.

Now for the vas deferens and seminal vessicles..