The Graffian follIcle of the Ovary is the correct answer. The follicular antrum is the portion of an ovarian follicle and this is filled with follicular fluid. This fluid is derived from the blood flowing through the thecal capillaires. The theca crosses the endothelium, subendothelial lamina before traversing the thecal intersititum, the follicular basal lamina and the membrana granulosa to reach the follicular antrum.