(a) Gross anatomy of the testis with a section cut away to reveal internal structures. (b) Cross section of a seminiferous tubule. Spermatogonia are near the periphery, and mature sperm cells are near the lumen of the seminiferous tubule. (c) Mature sperm cell. (d) Head of a mature sperm cell. Note: Vas deferens is sometimes called ductus deferens.
