The ovary (From Latin: ovarium, literally "egg" or "nut") is an ovum-producing reproductive organ. Ovaries in female individuals are analogous to testes in male individuals, in that they are both gonads and endocrine glands.
Histology
Follicular cells flat epithelial cells that originate from surface epithelium covering the ovary
Granulosa cells - surrounding follicular cells have changed from flat to cuboidal and proliferated to produce a stratified epithelium
Gametes
The outermost layer is called the germinal epithelium.
The ovarian cortex consists of ovarian follicles and stroma in between them. Included in the follicles are the cumulus oophorus, membrana granulosa (and the granulosa cells inside it), corona radiata, zona pellucida, and primary oocyte. The zona pellucida, theca of follicle, antrum and liquor folliculi are also contained in the follicle. Also in the cortex is the corpus luteum derived from the follicles.
The innermost layer is the ovarian medulla. It can be hard to distinguish between the cortex and medulla, but follicles are usually not found in the medulla.
The ovary also contains blood vessels and lymphatics.