The ovary. False-colour scanning electron micrograph of the external surface of the ovary known as the germinal epithelium. The swollen surface reflects the presence of a mature follicle beneath, known as the Graafian follicle, in which the ovum is almost ready to be ejected into the Fallopian tube. The turgidness is caused by an enlarged cavity in the follicle, the follicular antrum, in which fluid is stored. At ovulation the mature follicle ruptures and the ovum surrounded by a glycoprotein layer (zona pellucida) and a thick layer of cells (corona radiata) is expelled. Magnification: x65 at 6x7cm size. Magnification: x95 at 4x5 inch size.