Color enhanced scanning electron micrograph (SEM) of eggs surrounded by cumulus cells. Cumulus cells are granulosa cells that remain with the oocyte, or female gamete, after ovulation. They are located bellow the theca interna, separated from this layer by a basement membrane. Cumulus cells, surrounding the follicle that encases the oocytes, synthesize estrogen from the androgens produce by the theca interna, like all other granulosa cells.