FSH non-antral follicles: oocyte and granulosa cells. In panel a the oocyte (O) contains numerous organelles scattered in the ooplasm. A variable amount of microvilli (m, panel b) can be found on the oocyte surface (O, panels b, c). Both altered (panel a) and apparently healthy (panel d) granulosa cells (GC), often provided with surface expansions (panels c, e), are seen in the follicle wall. Panel a, asterisks: granulosa cell debris. Panels a, b, ZP: zona pellucida. Panel b, black arrow: cortical granule. Panels b, c, white arrows: granulosa cell cytoplasmic projections (transzonal processes). Panel d, TC: theca cells. Bar is: 2.5 μm (panel a); 0.6 μm (panel b); 26 μm (panel c); 5 μm (panel d); 36 μm (panel e). Panels a, b, d: TEM; panels c, e: SEM.