spermatogonium
| Spermatogonium | |
|---|---|
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| 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) | |
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| Histological section through testicular parenchyma of a boar. 1 Lumen of Tubulus seminiferus contortus, 2 spermatids, 3 spermatocytes, 4 spermatogonia, 5 Sertoli cell, 6 Myofibroblasts, 7 Leydig cells, 8 capillaries | |
| Gray's | subject #258 1243 |
| MeSH | Spermatogonia |
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.
Additional images
 Schematic diagram of Spermatocytogenesis |
Source
This article includes material from Biology Online.
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