A Graafian follicle, also known as an ovarian follicle, is a fluid-filled cyst-like cavity found in the ovaries. It surrounds and protects the developing ovum. Once the ovum is released into a Fallopian tube, the follicle develops a yellowish mass of tissue called the corpus luteum. Graafian follicles are named after Regnier de Graaf.

 

Graaf, Regnier de (1641–1673)

 

 

Regnier de Graaf was a Dutch anatomist and doctor who after whom the Graafian follicles are named. Graaf investigated the functions of the pancreas and the nature of the sexual organs. He was the first user of the term "ovary".