Spermatogenesis rku

Spermatogenesis is process of formation of spermatozoa in testes.

1. SPERMATOGENESIS Dr. R.K. Upadhyay PGT, Biology KV, 39 GTC, Varanasi cantt

2. Spermatogenesis   Formation of spermatozoa from germ cells Location - S eminiferous tubule of Testes Ploidy – Haploid (n) : 23 chromosomes

3.   T hree P hases Spermatocytogenesis (Mitosis ) Meiosis Spermiogenesis .

4. Steps of Spermtogenesis Proliferative phase : spermatogonia (A form and B form) → spermatocytes Meiotic phase : spermatocytes ( primary and secondary) → spermatids Differentiation phase ( spermiogenesis ): spermatids → spermatozoa

5. Proliferation Phase Stem cells are A spermatogonia   of seminiferous tuble undergo mitosis and form B spermatogonia cells. B Spermatogonia ndergo   spermatogenesis  to form mature  spermatozoa . TYPE A SPERMATOGONIA DARK NUCLEUS TYPE B SPERMATOGONIA PALE NUCLEUS

6. Meiotic Phase Each 1 o   spermatocyte divides to give rise to two short-lived secondary (2 o ) spermatocytes which in turn give rise to two  spermatids  each . The spermatids contain a haploid number of chromosomes.

7. Differentiation Phase ( spermiogenesis ) Mturation of spermatids in to spermatozoa . Major changes i ) formation of the  acrosome . ii )  condensation of nuclear chromatin   iii )  growth of the tail  

8. Spermiation Spermiation is the process by which mature spermatids are released from Sertoli cells into the seminiferous tubule lumen prior to their passage to the epididymis .

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