Primary oocyte

Primary oocyte
During oogenesis, the immature egg cell in which the first meiotic division begins, leading to the production of the first polar body and the secondary oocyte.

The primary oocyte grows much larger and completes the meiosis I, forming a large secondary oocyte and a small polar body that receives little more than one set of chromosomes.

In females gametogenesis is known as oogenesis and unlike males, all of the primary oocytes ever found in a female will be created in the ovarian follicles of the ovaries prior to birth.

"b) Unequal cell division in meiosis / 1 ovum and tiny polar bodies produced
b) Primary oocytes form before birth / growth phase before birth
b) Pause in meiosis at prophase I / further development suspended until puberty
b) Pause in meiosis at ...

Each month, approximately 1000 primary oocytes will to mature but most will die.
Ovulation occurs approximately once every 28 days. Females ovulate approximately 400 times during their lifetime.

Each egg begins oogenesis as a primary oocyte. At birth each female carries a lifetime supply of developing oocytes, each of which is in Prophase I.

oocyte Stage in formation of ovum, just preceding first meiotic division (primary oocyte) or just following first meiotic division (secondary oocyte).
ooecium Brood pouch; compartment for developing embryos in ectoprocts.

A small cell (which eventually disintegrates) that is the by-product of meiosis in female animals. One functional ovum and potentially three polar bodies result from meiosis of each primary oocyte.
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See also: Oocyte, Cell, Oogenesis, Egg, Cells