SPERMATOGONIA, SPERMATOGONIUM

Spermatogonium
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Spermatogonium

Germinal epithelium of the testicle. 1 basal lamina, 2 spermatogonia, 3 spermatocyte 1st order, 4 spermatocyte 2nd order, 5 spermatid, 6 mature spermatid, 7 Sertoli cell, 8 tight junction (blood testis barrier)


A spermatogonium (plural: spermatogonia) is an intermediary male gametogonium (a kind of germ cell) in the production of spermatozoa.

There are two subtypes:

Type A(d) cells have dark nuclei and they divide to produce copies of themselves, thereby ensuring a constant supply of spermatogonia to fuel spermatogenesis.

Type A(p) cells have pale nuclei and they divide by mitosis to produce Type B cells and these Type B cells divide again to give rise to primary spermatocytes.

Each primary spermatocyte duplicates its DNA and subsequently undergoes meiosis I to produce two haploid secondary spermatocytes. Each of the two secondary spermatocytes further undergo meiosis II to produce two spermatids (haploid). (1 primary spermatocytes => 4 spermatids)

The spermatids then undergo spermiogenesis to produce spermatozoa.


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