Introduction:-
• The process of formation of male gamete i.e sperm is called spermatogenesis.
• It occurs in the seminiferous tubules of testes.
• The germinal epithelium of seminiferous tubules largely consists of cuboidal primary germ cell which give rise to sperm by the process of spermatogenesis.
• It occurs in two successive steps such as
(I) Formation of spermatids
(II) Formation of spermatozoa
(I) Formation of spermatids:-
This process includes the following phases :-
(a) Multiplication phase:-
• At the onset of puberty, the undifferentiated primordial germ cells divide repeatedly by mitosis to produce large number of daughter cells called spermatogonia.
• A set of spermatogonia serve as stem cells which divide and redivide further to form more spermatogonia.
• The other set do not divide mitotically but develop and divide meiotically to produce sperm.
(b) Growth phase:-
• Spermatogonia, other than stem cells, grow in size by accumulating nutritive materials from surrounding supporting cells called Sertoli cells.
• These enlarged spermatogonia now called primary spermatocytes.
(c)Maturation phase:-
• This phase involves meiosis of primary spermatocytes.
• The first meiotic division is reductional reducing the chromosome number to half in each daughter cell.
• At this stage the two daughters cell called secondary spermatocytes.
• Each secondary spermatocytes undergoes the second maturation division which is equational.
• The daughter cells are known as spermatids.
• Thus at the end of two successive division four spermatids are formed.
(II) Formation of spermatozoa:-
• The second step of spermatogenesis doesn’t involve any division but transformation or metamorphosis of spermatids resulting in the formation of sperms.
• This process is called spermiogenesis.
Conclusion:-
The entire process of spermatogenesis takes approximately 64 days in man. After spermatogenesis sperm heads remain embedded in the Sertoli cells and are finally released from the seminiferous tubules by the process called spermiation.

PRESENTED BY:-Jyotshanashree Mohanty