Size of Graafian follicle?
Ans. b (20-23 mm). (Ref. William Obstetrics, 21st ed., 45, Langman's embryology 23)A graafian follicle is 20-23 mm in size.Ovarian Follicles As the primary oocyte begins to grow, surrounding follicular cells change from flat to cuboidal and proliferate to produce a stratified epithelium of granulosa cells, and the unit is called a primary follicle.|As development continues, fluid-filled spaces appear between granulosa cells. Coalescence of these spaces forms the antrum, and the follicle is termed a secondary (vesicular, Graafian) follicle.|Initially, the antrum is crescent shaped, but with time, it enlarges. Granulosa cells surrounding the oocyte remain intact and form the cumulus oophorus. At maturity, the secondary follicle may be 25 mm or more in diameter. It is surrounded by the theca interna.|With each ovarian cycle, a number of follicles begin to develop, but usually only one reaches full maturity. The others degenerate and become atretic. When the secondary follicle is mature, a surge in luteinizing hormone (LH) induces thepreovulatory growth phase.|Meiosis 1 is completed, resulting in formation of two daughter cells of unequal size, each with 23 doublestructured chromosomes. One cell, the secondary oocyte, receives most of the cytoplasm; the other, the first polar body, receives practically none.|Meiosis II is completed only if the oocyte is fertilized; otherwise, the cell degenerates approximately 24 hours after ovulation.
2-3 mm
20-23 mm
30-40 mm
15mm
The Ovarian Cycle