a-short-review-of-histology

Graafian Follicles:

In each cycle only one Graafian follicle reaches full maturity
A mature Graafian follicle has a primary oocyte surrounded by a zona pellucida and a cluster of follicular cells
This cluster of cells projects into the follicular fluid (antrum) as a small mound known as the cumulus oopherus
At ovulation, it is the follicular fluid plus the cumulus oopherus containing the oocyte surrounded by its zona pellucida and some follicular cells that is released from the surface of the ovary (triggered by a surge of luteinising hormone from the pituitary gland)
The Graafian follicle has a stratified layer of follicular cells which surrounds the antrum and the cumulus oopherus
This layer of follicular cells is known as the membrana granulosa
During maturation of the follicle, through the late secondary stages and Graafian follicle stages, the connective tissue stroma surrounding the follicle has also undergone a differentiation process to form a band of cells known as the thecal layer
This is subdivided into an internal highly vascularised layer (theca interna) and an external layer (theca externa)

Micrograph of Graafian Follicles: