Yours, Etc.: Origins and Uses of 8 Sign-Offs
spermatogenesis sper·mat·o·gen·e·sis (spər-māt'ə-jěn'ĭ-sĭs, spûr'mə-tə-)
Formation and development of spermatozoa by meiosis and spermiogenesis. Also called spermatocytogenesis.
The formation and development of spermatozoa. Spermatogenesis in humans begins with the spermatogonium, the diploid cell that undergoes mitosis to form new spermatogonia as well as cells called primary spermatocytes. Each primary spermatocyte then undergoes the first meiotic division to produce two secondary spermatocytes. Each secondary spermatocyte undergoes the second meiotic division to produce two nonmotile cells called spermatids. The four spermatids then develop flagella and become sperm. Since some of the original spermatogonia replace themselves, the males are able to produce large numbers of sperm continuously after sexual maturity.
the origin and development of the sperm cells within the male reproductive organs, the testes. The testes are composed of numerous thin, tightly coiled tubules known as the seminiferous tubules; the sperm cells are produced within the walls of the tubules. Within the walls of the tubules, also, are many randomly scattered cells, called Sertoli cells, that function to support and nourish the immature sperm cells by giving them nutrients and blood products. As the young germ cells grow, the Sertoli cells help to transport them from the outer surface of the seminiferous tubule to the central channel of the tubule.