Aspect of the ovarian external cortex observed with the objective of 10x. Under the epithelium lies the thin tunica albuginea, and below it there are some primordial and primary follicles, as well as larger secondary follicles surrounded by conjunctive stroma. Going from outside inwards we can distinguish the following layers in the primary follicles: follicular theca, granular layer (yellow), zona pellucida and the oocyte cytoplasm. The nucleus of one of them is also visible in the microphotography. The secondary follicle is covered by a follicular theca, and below it, there is a thin granular layer that extends itself towards the oocyte in the cumulus oophorus, surrounded by the free space of the follicular antrum. Around the oocyte of the secondary follicle is located the zona pellucida.