Female gametogensis

Question 1

When does gametogensis begin?

Answer 1

in utero at 4 weeks gestation

primordial germ cells migrate from the yolk sac to developing gonads

Question 2

describe the replication of germs cells and the progression through meiosis at the various stages

Answer 2

in utero germ cells differentiate into oogonia and multiply by misosis before begining meiosis 1

meiosis 1 is arrested prophase 1 leaving primary oocytes, which are completely formed by 5 months but remain arrested until ovulation, when FSH stimulation followed by the LH surge causes some primary oocytes to resume miosis 1, yeilding secondary oocytes and polar bodies

secondary oocyte begins miosis 2 and is arrested in metaphase 2 until fertilization occurs (the 1st polar body degerates). Once fertilized, mature ovum and second polar body are formed from telophase II.

normally fertilized embryo is diploid