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Spermatogenesis is the process by which male spermatogonia develop into mature spermatozoa. Spermatozoa are the mature male gametes in many sexually reproducing organisms. Thus, spermatogenesis is the male version of gametogenesis. In mammals it occurs in the male testes and epididymis in a stepwise fashion, and for humans takes approximately 64 days. Spermatogenesis is highly dependent upon optimal conditions for the process to occur correctly, and is essential for sexual reproduction. It starts at puberty and usually continues uninterrupted until death, although a slight decrease can be discerned in the quantity of produced sperm with increase in age. The entire process can be broken up into several distinct stages, each corresponding to a particular type of cell: Cell type ploidy/chromosomes chromatids Process spermatogonium (types Ad, Ap and B) diploid/46 2N spermatocytogenesis (mitosis) primary spermatocyte diploid/46 4N spermatidogenesis (meiosis 1) secondary spermatocyte haploid/23 2N spermatidogenesis (meiosis 2) spermatid haploid/23 1N spermiogenesis sperm haploid/23 1N spermiation A mature human SpermatozoonFrom Wikipedia under the
GNU Free Documentation License  users.rcn.com 517px x 362px | 62.60kB [source page] soil profile gif 29 Aug 2004 14 35 19k sori004 jpg 29 Jul 2007 17 59 40k spermatogenesis gif 29 Aug 2004 14 35 63k squid heart gif 29 Aug 2004 14 35 32k  just.edu.jo 549px x 400px | 40.10kB [source page] were sequentially arranged along the length of the tubule Figure 10 As the cycle progress this arrangement resulted in a wave of spermatogenesis along the tubule Fig 10 Spermatogenesis jpg Figure 10 The pattern of the stages of spermatogenesis as they occur along the tubule are shown  faculty.clintoncc.suny.edu 364px x 486px | 90.60kB [source page] Spermatogenesis in the Testis From Yahoo Image Search: "spermatogenesis"  news.google.com 7thSpace Interactive (press release) We attribute that the transcriptional activity of rDNA genes in the late spermatogenesis is due to the presence of this variant NRP. ... news.google.com This is London ... it is but a short wriggle from achieving successful spermatogenesis in the lab to the annihilation of anything human which has in our charming cockney ... and more » news.google.com 7thSpace Interactive (press release) Post-meiotically expressed genes in the testis are essential for the proper progression of spermatogenesis , and yet, aside from the construction of ... From Google News Search: "spermatogenesis"  jbc.org Choi, E., Han, C., Park, I., Lee, B., Jin, S., Choi, H., Kim, DH, Park, ZY, Eddy, EM, Cho, C. 2008-12-05 08:00:00 To determine the mechanisms of . spermatogenesis. , it is essential to identify and characterize germ cell-specific genes. Here we describe a protein encoded by a novel germ cell-specific gene, Mm.290718/ZFP541, identified from the mouse ...  elitefitness.com RxHealthDrugs 2009-05-12 02:15:50 Owing to active ingradients, tribelus influences reproductive function, . spermatogenesis. , ovulation and sexual activity of both sexes, stimulating it, and also possesses tonic action. What is it used for?: ...  apitherapy.blogspot.com Editor 2008-12-08 06:00:00 In conclusion, our results show that ingestion of honey induces . spermatogenesis. in rats by increasing epididymal sperm count, increasing selectively the relative weight of the epididymis, and increasing SDH activity and reducing LDH ... From Google Blog Search: "spermatogenesis" |
