Primordial germ cells reach the ovary in 5th week ↓ All primordial germ cells get converted to oogonium by 3rd month ↓ All oogonia get converted to primary oocyte by 5th – 7th month ↓ Completes only prophase ↓ Go to resting phase ( Diplotene phase ) [ remain in resting phase until puberty ]

Spermatogonium undergoes 5-7 cycles of division to form primary spermatocyte So one spermatogonium forms 64-512 spermatozoa. I primary spermatocyte ➡️ 4 spermatid Difference between spermatogenesis and oogenesis Spermatogenesis Oogenesis process starts only after puberty process begins in intrauterine life polar body absent polar body present i primary spermatocyte ➡️ 4 spermatid i primary oocyte ➡️

It is pluripotent Synthesized by epiblast in 2nd week → Migrate to endodermal wall yolk sac in 4th week → Reach the gonads by 5th week Sometimes the PGC reach the neck region (craniopharyngeal teratoma) and sometimes they migrate to the region between sacrum and coccyx (sacrococcygeal teratoma). The term “Teratoma” is used because of