<P> Oogonia that are undergoing degeneration appear slightly different under the electron microscope . In these oogonia, the chromosomes clump together into an indistinguishable mass within the nucleus and the mitochondria and E.R. appear to be swollen and disrupted . Degenerating oogonia are usually found partially or wholly engulfed in neighboring somatic cells, identifying phagocytosis as the mode of elimination . </P> <P> In the blastocyst of the mammalian embryo, primordial germ cells arise from proximal epiblasts under the influence of extra-embryonic signals . These germ cells then travel, via amoeboid movement, to the genital ridge and eventually into the undifferentiated gonads of the fetus . During the 4th or 5th week of development, the gonads begin to differentiate . In the absence of the Y chromosome, the gonads will differentiate into ovaries . As the ovaries differentiate, ingrowths called cortical cords develop . This is where the primordial germ cells collect . </P> <P> During the 6th to 8th week of female (XX) embryonic development, the primordial germ cells grow and begin to differentiate into oogonia . Oogonia proliferate via mitosis during the 9th to 22nd week of embryonic development . There can be up to 600,000 oogonia by the 8th week of development and up to 7,000,000 by the 5th month . </P> <P> Eventually, the oogonia will either degenerate or further differentiate into primary oocytes through asymmetric division . Asymmetric division is a process of mitosis in which one oogonium divides unequally to produce one daughter cell that will eventually become an oocyte through the process of oogenesis, and one daughter cell that is an identical oogonium to the parent cell . This occurs during the 15th week to the 7th month of embryonic development . Most oogonia have either degenerated or differentiated into primary oocytes by birth . </P>

Identify the name and number of cell(s) produced by ogonia when divided through mitosis