Oogenisis before Ovulation Process
Oogenisis is Process of mature ovum .It is start during fetal life.Million of mother germ cell (Oogonia) develop in fetus.
No any Oogonia are develop after birth .Oogonia divided by mitotic division from primary oocyte. It is associated with granulosa cell from primary follicles.
After birth up to puberty is large no of primary follicles degenerated about 60,000 to 80,000 primary follicles left in each ovary.
Primary follicles now associated with theca layer to from secondary follicles .Theca layer differentiated into theca Externa(outer) and theca interna (inner) .Theca interna secret Estrogen.
Secondary follicles change into tertiary follicles. It is characteristic by fluid filled cavity called antrum .
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Primary oocyte or tertiary follicles in large in size and become mature primary oocyte.Now undergoes mitotic first division to produce secondary oocyte small polar first body.
It is unequal division. By the influence of Estrogen and FSH (Follicle-stimulating hormone). from Pituitary .Tertiary follicles transform into Graafian follicles.
Now secondary oocyte of Graafian follicles form a new membrane is called zona pellucida .Graafian follicles release secondary oocyte by the process called Ovulation.
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