Ovary

This image shows several zona pellucidae of atretic secondary (or preantral) follicles and two tertiary follicles. Note the relatively small antrum but distinct cumulus oophorous . The follicle with the large antrum could be a very large follicle, but we cannot tell its real size. However, the granulosa cells appear to be degenerating, so we can call this a tertiary follicle undergoing early atresia. UCLA Histology Collection.