Physiology of Finfish and Shellfish (2+1)

3.1.9. Ovarian follicle

The ovary consists of germ cells, oogonia and oocytes and their surrounding follicle cells and supportive tissues. The ovarian follicles arise from the germinal epithelium as each germ cell becomes surrounded by a layer of follicle cells early in development.

With growth, the follicle cells multiply and form a continuous layer known as the granulose cell layer. At the same time, the outer layers of connective tissues become organized to form a follicular envelope or thecal cell layer. Thus, the developing oocyte becomes surrounded by 2 major cell layers, the inner granulose layer and the outer thecal layer. The granulose and thecal cell layers are separated from each other by a distinct basement membrane. (Fig).