tertiary egg membrane -->
egg membrane
medical dictionary

The investing envelope of the ovum; a primary egg membrane is produced from ovarian cytoplasm (e.g., a vitelline membrane); a secondary egg membrane is the product of the ovarian follicle (e.g., the zona pellucida); a tertiary egg membrane is secreted by the lining of the oviduct (e.g., a shell).

(05 Mar 2000)