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The process of spermatogenesis as the cells progress from primary spermatocytes, to secondary spermatocytes, to spermatids, to Sperm Cycle of the seminiferous epithelium of the testis. Spermatocytogenesis is the male form of gametocytogenesis and results in the formation of spermatocytes possessing half the normal complement of genetic material.
During spermatogenesis, the DNA of spermatogenic cells in the seminiferous tubules is subject to damage from such sources as reactive oxygen species. [1] The genomic integrity of spermatogenic cells is protected by DNA repair processes. [2] Deficiencies in the enzymes employed in these repair processes may lead to infertility. [2]
An important discovery in the spermatogenesis process was the identification of the seminiferous epithelial cycle in mammals—work by C.P. Leblound and Y. Clermont in 1952 that studied the spermatogonia, spermatocyte layers and spermatids in rat seminiferous tubules.
The sperm cells are the only flagellated cells in the life cycle of these plants. In many ferns and lycophytes, cycads and ginkgo they are multi-flagellated (carrying more than one flagellum). [34] In nematodes, the sperm cells are amoeboid and crawl, rather than swim, towards the egg cell. [35]
The second cell type is the cells belonging to the spermatogenic cell lineage. These eventually develop into sperm cells (spermatozoon). Typically, the spermatogenic cells will make four to eight layers in the germinal epithelium. [1]
A spermatogonium (plural: spermatogonia) is an undifferentiated male germ cell.Spermatogonia undergo spermatogenesis to form mature spermatozoa in the seminiferous tubules of the testicles.
For those SSCs destined to form differentiating progenitor A1 spermatogonia (and hence spermatozoa), this is initiated at a defined stage during the spermatogenic cycle. [7] The precise location of SSCs throughout various staged cohorts of the seminiferous tubule determines their renewal function, to continuously produce progeny. [ 1 ]
Male monotremes are testicond (have intraabdominal testes) with the testes undergoing seasonal emergence during winter. The fully developed seminiferous tubules exhibit distinctly small stages of spermatogenesis in that more than one stage is often observed in a cross section of the tubule, [3] a characteristic of spermatogenesis that has also been observed in a reptile, [4] common in birds [5 ...