Antral follicle

The antral or secondary follicle is one of several stages of development of the growing Graafian follicle.

Development to the antral follicle stage
As the follicle matures, changes occur - the oocyte grows rapidly, flat follicular cells proliferate and take on a cuboidal shape. Follicular cells divide and subsequently form the membrana granulosa (multilayered epithelium). At this point, we call the follicle a multilayered  primary follicle. Between the oocyte and the follicular cells, a wide envelope is formed - the zona pelucida. The ovarian stroma adjacent to the follicle also differentiates in the theca folliculi (we distinguish between theca interna and theca externa). As the follicle grows, a fluid called liquor folliculi accumulates between the granulosa cells. The cavities created in this way with the liquor folliculi then merge and form a cavity - the antrum. This follicle is already referred to as a secondary (antral) follicle.

Related articles

 * Ovary
 * Menstrual cycle
 * Graafian follicle