Seminiferous tubules. Light micrograph of a section through seminiferous tubules, the site of sperm production in the human testis. Each testis is packed with numerous convoluted seminiferous tubules, loops of which are cut here at various angles. The tubules are lined by a stratified epithelium containing two types of cell: Sertoli cells, which nourish developing sperm, and spermatogenic cells, which produce the sperm. The sperm are released into the cavity (white) of each tubule to migrate to the epididymis, where they mature. Between the seminiferous tubules are Leydig cells, which produce testosterone. Magnification: x40 at 6x7cm size.