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Gametogenesis


GAMETOGENESIS
(by MAAZ AHMED SIDDIQUI)
GAMETOGENESIS:
It is a process by
 which diploid or haploid cells undergo cell division and differentiation to form mature haploid gametes
SPERMATOGENESIS:
       Is the process of formation of the male germ cells (sperm formation).
       It occurs in the seminiferous tubules of the testis.
       It is thread-like in shape.
Spermatogenesis occur from puberty to old age , producing immense numbers of spermatozoa at an average rate of 1.5 million spermatozoa per minute.
       The sertoli cells are supporting cells that have several functions.
       They form the blood-testes barrier: nutrients , and circulating substances do not directly reach the germ cells.
       The sertoli cells determine which substances reach the germ cells.
       The spermatogonia are outside the blood-testis barrier.
       They are produce antigen-binding proteins , which are necessary for spermiogenesis ( morphological development of spermatids to spermatozoa)
       Spermatogenesis is the process by which male primary sperm cells undergo meiosis , and produce a number of cells termed spermatogonia , from which the primary spermatocytes are derived.
       Each primary spermatocyte divides into two secondary spermatocytes , and each secondary spermatocyte into two spermatids or young spermatozoa.
       These develop into mature spermatozoa, also known as sperm cells.
       The primary spermatocytes gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa.
OOGENEIS IS THE PROCESS OF FORMATION OF THE FEMALE GERM CELLS (EGG FORMATION)
       All oocytes formed in females are produced during foetal life. Many of them degenerate with time and at birth the ovaries contain about 2 million oocytes.
       All the oocytes go into meiotic arrest when they reach the first meiotic division during foetal life.
       The primary oocytes remain in the
prophase of the first meiotic division until the time of puberty , when they are gradually released to complete meiosis at regular intervals known as the ovarian cycle.
       On the average only one oocyte matures during each cycle, which occurs at approximately monthly intervals, so that the amount of oocytes to be ovulated is about 500 oocytes in a life.



Gametogenesis Gametogenesis Reviewed by Maaz ahmed siddiqui on 07 May Rating: 5

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