Before birth, primordial germ cells undergo mitosis, producing ~2 million oogonia, Every oogonia (within follicles) begins meiosis, with now Primary Oocytes arresting at prophase I, Every month from puberty, one primary oocyte will resume meiosis from prophase I, After this stage, a primary oocycte has become a secondary oocyte, paused at metaphase II and a polar body is produced, During ovulation, a secondary oocyte is released from the ruptured follicle., The ruptured follicle becomes the luteal body - a crucial part of hormonal control of female reproductive cycles., Fimbriae sweep the ovulated secondary oocyte into the fallopian tube., IF Fertilisation occurs, the union of sperm and secondary oocyte causes meiosis II to resume and finish, resulting in a mature (fertilised) ovum, and a second polar body to be produced., IF Fertilisation does not occur then the secondary oocyte degenerates (within the fallopian tube)., Many of the follicles will degenerate in a process called atresia, long before resuming/completing meiosis - this phenomenon is what leads to menopause.

Oogenesis - Processes

by
Print
Embed

Leaderboard

Visual style

Options

Switch template

Continue editing: ?