Spermatogenesis

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1. Spermatogonial stem cells undergo mitotic division to regenerate their own numbers and produce A1 spermatogonia
2. A1 spermatogonia undergo mitotic division (although cytoplasm remains joined by thin bridges) through A1-4 and type intermediate (in rats) spermatogonia
3. Type intermediate spermatogonia become type B spermatogonia and enter resting phase as resting primary spermatocytes.
4. Resting primary spermatocytes duplicate DNA and then move into adluminal compartment of seminiferous tubules
5. Then enter meiosis I to generate secondary spermatocytes
6. Meiosis II leads to early spermatids all joined by cytoplasmic bridges
7. Cytoplasmic remodelling takes place (spermiogenesis)
   1. Tail generated
   2. midpiece forms containing mitochondria
   3. equatorial and post acrosomal cap
   4. acrosome develops
   5. .nucleus contains compact, packaged DNA
   6. Residual body contains residue and is phagocytosed by Sertoli cells shortly after sperm released.
8. release of cells into lumen of tubule called spermiation..

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