Sketch and label the Graafian follicle showing theca externa, antrum and corona radiata.

Answer: [Diagram: a large spherical Graafian (mature) follicle. Outermost fibrous layer labelled theca externa, inside it the vascular theca interna, then a layer of granulosa cells (membrana granulosa). A large fluid-filled cavity labelled antrum (containing liquor folliculi). On one side a mound of granulosa cells (cumulus oophorus) carrying the secondary oocyte, which is surrounded by the zona pellucida and an outer ring of radially arranged follicle cells labelled corona radiata.]

The Graafian follicle is the mature ovarian follicle that ruptures at ovulation (about day 14) to release the secondary oocyte along with the corona radiata.