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Producing oocytes.


Producing oocytes (ova).
Synonym(s): ovigenetic, ovigenic.
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(o?o-jen'e-sis) [? + genesis, generation, birth]
The developmental process by which the mature human ovum (the female reproductive cell) is formed. Formation begins during the first 3 months of female embryonic life with the development of ovarian follicles. Each follicle contains one oogonium which, through the process of mitosis, becomes a primary oocyte containing 46 chromosomes. The oocyte then undergoes the first meiotic reduction division, resulting in formation of a secondary oocyte and a polar body, each containing 22 autosomes (half the number of chromosomes that are found in nongerm cells) and one X heterosome. Further division is arrested in prophase until the female reaches puberty. The second meiotic division begins at ovulation and reaches metaphase where, once again, division is arrested until the ovum is fertilized. The second meiotic division is completed at fertilization, ending with formation of the mature haploid ovum and one polar body. Synonym: ovigenesis
See: illustration; meiosisoogenetic (-je-net'ik), adjective