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Oogenesis occurs in the ovary.
Primordial germ cells migrate from the wall of the
yolk sac during embryonic development and enter the developing ovary. These differentiate into oogonia. Some of the oogonia are arrested in the prophase of meiosis I and become primary oocytes. The primary oocytes are surrounded by a single layer of flattened epithelial cells to form primordial follicles. They remain in this state until the individual reaches puberty.

At puberty primordial follicles begin to mature into
primary follicles at the rate of about one per month for the entire reproductive life of the woman (to about age 50).

As the follicle matures, the
primary oocyte completes its first meiotic division to give rise to a secondary oocyte and a smaller polar body.

After ovulation, if fertilization takes place, the
secondary oocyte undergoes the second meiotic division to become an ovum and a second polar body.

Both the ovum and the polar body are contained within a glycoprotein shell called the
zona pellucida.

The follicle cells of the ovary develop into a
corpus luteum, an endocrine gland that produces hormones to maintain the wall of the uterus in its progestational state.