The follicular cells produce a fluid that coalesces to form an antrum, the presence of which defines a secondary follicle. The follicle cells lining the antrum and surrounding the oocyte are now called granulosa cells. The zona pellucida, composed of glycoproteins around the enlarged oocyte, is surrounded by granulosa cells called the corona radiata. The entire mass of granulosa cells and the oocyte are referred to as the cumulus oophorus.
Secondary Follicle Med Mag.