Testis and Epididymis

#56 Testis and Epididymis, Human, Adult, H&E (scanned slide is testis only)

Identify the following structures with the naked eye and low magnification: 1) tunica albuginea - the fibrous capsule surrounding the testis; 2) mediastinum - the mass of acidophilic connective tissue at one pole through which the major vessels enter and leave the testis; 3) epididymis - the convoluted duct next to the mediastinum; 4) rete testis in the mediastinum.

At higher magnification identify the germinal elements (spermatogonia, spermatocytes and spermatids) and sustentacular (Sertoli) cells in the seminiferous tubules. Only the Sertoli cells and spermatogonia (usually with interphase nuclei) rest on the basement membrane. The larger primary spermatocytes lie on the luminal side of the Sertoli cells and are frequently in some stage of the prolonged prophase of the first meiotic division. Secondary spermatocytes rapidly undergo the second meiotic division and are therefore rarely seen. During spermiogenesis the spermatids are remodeled into streamlined motile cells, the spermatozoa. The entire process of gamete production (i.e., spermatogonia to spermatozoa) is known as spermatogenesis. The germinal elements characteristically occur in small associations of synchronized cells. Beneath the basement membrane of the tubules note the myoid cells (myoepithelium) with their pale-staining elongated nuclei.

In the interstitium (between the seminiferous tubules) identify Leydig cells, which are large eosinophilic cells. Why are they eosinophilic?

Note also the histological characteristics of the efferent ductules (on slide #56), the epididymis (see previous page) and the storage of spermatozoa in the tail (cauda) of the epididymis.

#57 Testis and Epididymis, Monkey, Rabbit, H&E

Be sure that you distinguish the testis and the epididymis.

#2 Epididymis, Rat (Silver stain for Golgi)

The epididymis is the major site of sperm maturation and storage. The epithelial cells are absorptive and also secrete products required for maturation of sperm. The nucleus is in the basal part of the epithelial cell and is stained pinkish-red. The Golgi apparatus is stained black with silver. Note its position between the nucleus and cell apex. Note the stereocilia at the apices of the cells. Recall that they are modified microvilli and are non-motile.

<<Back