Ovogenesis

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Ovogenesis(from the Latin. ovum - egg and Greek. yeveo i s; - origin), ovogenesis is the process of development of the human egg cell, which occurs in the ovum and includes periods of reproduction, growth and maturation. The reproduction period is characterized by an increase in the number of primary germ cells (ovogoniyev) as a result of their reproduction by means of timothitis.

This period ends at the moment of birth of the fetus. During the growth period, the division of ovogoniyev stops and they are called 1st order oocytes. At the beginning of the period, the oocyte increases slightly, but in the nucleus of its occurring processes that prepare the reduction genetically. material (previtellogenesis). At the end of this period, the oocyte grows rapidly (sometimes its volume increases tens of thousands of times) and accumulates the yolk (vitellogenesis).

Nek-ry oocytes go deep into walls of an ovary, become covered by the follicular cells developing from its somatic cells, forming a follicle. Under the influence of pituitary hormones, follicular cells secrete steroid hormones that promote the maturation of the oocyte. The period of maturation of gametocytes, or period meiosis, includes 2 successive divisions.As a result of the first, an oocyte of the 2nd order and the first polar body are formed, and after the second - a mature, capable egg fertilization and the second polar body. See also Gametogenesis, Spermatogenesis.

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