A subpopulation called type A spermatogonia act as stem cells, dividing to produce new stem cells and other type A spermatogonia that undergo transit
amplification as progenitor cells. Mitosis in these cells occurs with incomplete cytokinesis, leaving the cytoplasm of most or all of these cells connected by
cytoplasmic bridges. Type A spermatogonia divide mitotically two or three more times, then differentiate as type B spermatogonia that undergo a final
round of mitosis to form the cells that then enter meiosis and become primary spermatocytes (only two are shown), still interconnected. The intercellular
bridges persist during the first and second meiotic divisions, but they are lost as the haploid spermatids differentiate into sperm (spermiogenesis) and shed
excess cytoplasm as residual bodies. The interconnections of the cells allow free cytoplasmic communication among the cells and help coordinate their
Source: Chapter 21. The Male Reproductive System, Junqueira’s Basic Histology, 13e
progress through meiosis and spermiogenesis.
Citation: Mescher AL. Junqueira’s Basic Histology, 13e; 2013 Available at: http://mhmedical.com/ Accessed: July 28, 2017
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