Question

What happens to the Graafian follicle after ovulation?

Answer 1

Hint: The Graafian follicle is one of the stages of human oocyte development. It is when the first meiotic division has taken place, but not the second, and therefore contains a 2N oocyte which is haploid.

Complete Answer:
Most of the Graafian follicle consists of a central zone or Antrum, and the developing oocyte is placed to one side of the follicle wall. It is also called a vesicular ovarian follicle because of this large, fluid-filled antrum. Within the Graafian follicle, under the influence of oestrogen, the oocyte continues to develop. A mature egg cell released from this is surrounded by a Zona Pellucida and Corona Radiata. The second meiotic division of the oocyte does not take place until the egg has been fertilised by the sperm cell.

The effect of luteinizing hormone stimulates the Graafian follicle to rupture and turns it into the yellowish corpus luteum. The Corpus Luteum then continues to secrete progesterone, the main hormone which will help in pregnancy.

In terms of size, the Graafian follicles are quite large, growing to just under 2 centimetres at ovulation. Two types of these follicles exist: the healthy ones which will mature and produce healthy egg cells, and the atretic follicles which undergo apoptosis or programmed cell death. Graafian follicles themselves form from primary follicles which are present in the female ovaries at birth via an intermediate stage of secondary follicles.

Note: While in the male reproductive system, spermatocytes can undergo thousands of cell divisions to produce millions of primary spermatids, the number of primary oocytes in the female reproductive system is fixed at birth.