A colorized scanning electron micrograph of a human egg, which is the huge cell colored yellow at the bottom of this image. The follicle cells that surround it (top) send out long projections that penetrate through the tough outer coating (the zona pellucida) into the egg cell itself giving it the nourishment it needs to develop to maturity. Even when the egg is released from the ovary at ovulation it remains surrounded by a cloud of follicle cells that only gradually fall away as the egg progresses along the Fallopian tube.