Assertion: oocyte's follicle | /r/AtLocation | cortical layer of the ovary
Facets:
value: at 17 days
type: TEMPORAL
Source sentences:
text: At 17 days, primordial follicles, each of consists of a small oocyte and a single layer of flattened pre-granulosa cells, can first be observed in the cortical layer of the ovary.