An exam question asked what stage of meiosis corresponds with "first meiotic arrest of oogenesis". I can't work out the answer from the wiki page - can anyone explain which step this refers to?
Answer
When females are in their mother's womb all their Oogonium (plural Oogonia) are being made, they they undergo mitotic divisions to become a primary oocyte. Then, the primary oocytes start to undergo meiosis I - but meiosis I is arrested. This is the first meiotic arrest. Meiosis I continues when a female hits puberty, every month one or more primary oocytes undergo meiosis I and create secondary oocytes. These secondary oocytes will then start the second meiotic division, but this second meiotic division is arrested as well. It is arrested for about 24 hours, waiting for a sperm to fertilise it in the Fallopian tubes. The only time an egg (or in medical terms - secondary oocyte) will complete meiosis II is if a sperm penetrates the egg, and then it is called an ovum, which develops into a zygote and a then foetus.
Therefore, the answer to your question will be - the first meiotic arrest in oogenesis will occur from the time the primary oocytes are created in the womb, until a female reaches puberty. starting puberty until menopause every month one or more primary oocytes will mature and complete the first meiotic division.
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