Gametogenesis
– It is the formation of gametes in the gonads.
– Includes Spermatogenesis and Oogenesis.

Spermatogenesis

• It is the process of formation of sperms (spermatozoa) in seminiferous tubules of the testis. It has 2 stages: Formation of spermatids and Spermiogenesis
• a.Formation of spermatids: In this, Spermatogonia
  (Sperm mother cells or immature male germ cells) produce spermatids.
• b.Spermiogenesis:

                                          Spermatids transform into sperm.
                                                         ↓ Mitosis differentiation
                                                 Prim. spermatocytes (2n)
                                                         ↓1st meiotic division
                           Sec. spermatocytes -n (Haploid, 23 chromosomes)
                                                         ↓2nd meiotic division
                                                  Spermatids (n)
                                                         ↓ Differentiation
                                                  Spermatozoa (n)

• Each Primary spermatocyte produces 2 secondary spermatocytes.
• Each secondary spermatocyte produces 2 haploid spermatids. Thus 4 spermatids are formed from each primary spermatocyte.
• After spermiogenesis, sperm heads become embedded in the Sertoli cells and are finally released from seminiferous tubules. It is called spermiation.