Primordial follicles consist of an oocyte and a single layer of surrounding squamous follicle cells. Primordial follicles are immature ovarian follicle that has not undergone recruitment yet and consists of a primary oocyte enclosed by a single layer of squamous granulosar. It becomes the primary follicle when granulosa cells become enlarged and cuboidal, and form more than one layer and then a layer called zona pellucida forms around the primary oocyte.
