Figure 1.

Unrestricted spermatogonial testis. Schematic drawing illustrating the changes of the continuity and discontinuity of the germinal epithelium (GE) during the annual reproductive cycle. The continuity is observed when spermatogonia and/or cysts with germinal cells are continuous along the lobular lumen. During spermiation, the discontinuity is observed when there are portions where there are no germinal cells, only Sertoli cells. The 5 phases of the reproductive cycle are illustrated: Regressed, Early GE Development, Mid GE Development, Late GE Development and Regression. Lobular lumen (L), Sertoli cells (SE), spermatogonia (SG), dividing spermatogonia (DSG), spermatocytes (SC), spermatids (ST), spermatozoa (SP).