Question

Describe the development of a sperm cell.

Answer 1

DEVELOPMENT OF A SPERM CELL

1. Sperms are produced by the process of spermatogenesis.
2. About 300 millions of sperms are produced each day by the process of spermatogenesis.
3. The cross section of seminiferous tubule shows the stages of the sperm development.
4. The process of spermatogenesis is initiated by the diploid cell (46 chromosomes) called spermatogonium.
5. Now spermatogonium produces primary spermatocyte that further undergoes the meiotic division and produces secondary spermatocytes.
6. There are 2 stages of meiotic division take place: in first division it produces secondary spermatocytes whereas in second division it produces spermatids.
7. Both the cells secondary spermatocytes and spermatids are haploid cells (23 chromosomes).
8. The spermatids are then folds into sertoli cell’s cytoplasm and converts into the mature form known as spermatozoa that are released into the lumen of the tubule.
9. Normally it takes 74 days to form spermatozoa from spermatogonium.
10. It is assumed that one spermatogonium produces 512 spermatids approximately.

REFERENCE: http://www.emc.maricopa.edu/faculty/farabee/biobk/gametogen_2.gif

Answer 2

In testis, immature germ cells(spermatogonia) produces sperms by spermiogenesis.
the spermatogonium present on inside wall of seminiferous tubules multiply
BY MITOTIC DIVISION .
EACH SPERMATOGONIUM IS DIPLOID.
CONTAIN 46 CHROMOSOMES.
some of spermatogonia called primary spermatocyte
UndERGO MEIOSIS.
PRIMARY SPERMATOCYTE COMPLETES FIRST MEIOTIC DIVISION
leading to formation of
 2EQUAL HAPLOIDCELLS CALLED SECONDARY SPERMATOCYTES which
have ONLY 23 CHROMOSOMES EACH.
secondary spermatocyte undergo
2Nd MEIOTIC DIVISION
TO PRODUCE
4 EQUAL HAPLOID SPERMATIDS.
spermatids are transformed into sperms by SPERMIOGENESIS.
after spermiogenesis sperm head embed in sertoli cells
nd then relased by SPERMIATION
spermatogenesis starts at puberty due To
INCREASE IN GnRH which acts at ant.pit.and stimulates LH (acts on leudig cells)secrete androgens which in turn
STIMULATE SPERMATOGENESIS