Capsule – covers the outer surface.
Germinal Epithelium – the surface is covered by a simple cuboidal epithelium.
Tunica Albuginea – layer of dense irregular connective tissue that supports the epithelium.
Cortex – outer region that is the site of oocyte development.
Ovarian Follicles – oocytes surrounded by one or more layers of cells.
Primordial Follicles – oocytes arrested in development are located in the outer cortex.
Primary Oocyte – large (25 to 30 µm), round to oval cells with a vesicular nucleus.
Zona Pellucida – layer of glycoproteins between the oocyte and granulosa cells. It is visible a thin, eosinophilic band in many follicles.
Follicular Cells – single layer of flattened cells that surround each oocyte.
Primary Follicles – primary oocytes surrounded by one or more layers of cuboidal-shaped granulosa cells (which develop from follicular cells).
Unilaminar (#1, #2 and #3) – primary oocytes surrounded by a single layer of granulosa cells.
Multilaminar (#1 and #2) – primary oocytes surrounded by multiple layers of granulosa cells.