FIGURE 1.

Epididymal epithelial cells and luminal microenvironment are important for male reproduction. (A) Graphic illustration of the generation of spermatozoa in the testis through spermatogenesis, the maturation of spermatozoa in the epididymis, and the spermatozoa functions, including sperm hyperactivation, acrosome reaction and sperm-egg interaction, in the female reproductive tract required for fertilization. (B) The different cell types in the various regions of epididymis, including basal cells, clear cells, narrow cells, and principal cells, as well as immunological cells from systemic circulation. These different cell types work in a concerted manner to form a unique luminal microenvironment that promotes maturation of sperm during its epididymal transit and ensures male fertility.