Spermatogenesis & The Uterine Cycle

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I. Spermatogenesis.

Spermatogenesis is the process of producing a sperm that starts at puberty, continuing through the rest of his life (Farabee, 2010, May 18). It starts in the seminiferous tubules of the testes where the process of producing a sperm generally takes 64 to 72 days (Chute, 2009; Henderson, n.d.). The spermatogenic cells in the seminiferous tubules are always in various stages of cell division (Chute, 2009, Spermatogenesis section, para. 2). The parent cell, spermatogonium, is the outermost cells in contact with the epithelial basal lamina (Chute, 2009; Henderson, n.d.). The spermatogonium divides by mitosis into two cells, type A and type B (Chute, 2009; Snyder, 2010, July 18). Type A will maintain the stem cell line and remain at the basement membrane, and type B cell moves toward the lumen to become a primary spermatocyte (Chute, 2009; Henderson, n.d.).

The primary spermatocyte undergoes meiosis I reducing the number of chromosomes in a cell from 46 to 23 by separating homologous chromosomes into two haploid cells secondary spermatocytes (Snyder, 2010, July 18; Chute 2009). The secondary spermatocytes undergo meiosis II to form early spermatids (Henderson, n.d.). Spermatozoa, produced by males, contain a 23rd chromosome that is either an X chromosome (female) or the analogous Y chromosome (male), making each ...