The human oocyte goes through several developmental states: Oogonium - primary oocyte - secondary oocyte - mature ovum.
An oocyte is inside a follicle. There are several developmental stages of ovarian follicles:
In secondary follicle the oocyte is covered in multilayerd cuboid epithelium (Stratum granulosum). This epithelial layer is divided from the oocyte by a gylcoprotein rich layer (Zona pellucida). On the outside of the epithelium there is a thin membrane (basal lamina).