Mature Graafian follicle is generaly present in the ovary of a healthy human female
11th - 17th day of menstrual cycle
Starting from puberty, monthly changes in ovaries and uterus also starts. The layer of cells surrounding primary oocyte are called Granulosa cells. These cells together with the oocyte are called primary follicles.
The growth of the follicles is under the influence of pituitary hormones FSH and LH. Further growth is also stimulated by estrogen. The mature Graafian follicle is present in the ovary around 11-17th day of menstrual cycle and on rupture of which, ovum is released (because of LH surge, 1-2 days before ovulation).