Parietal yolk sac

Definition

Tissue that consists of two cellular layers (parietal endoderm and trophoblast) separated by a relatively thick nonvascular basement membrane (Reichert's membrane), and acts as a protective layer to supports and facilitates transport of nutrients between the uterine tissue and the yolk sac cavity.

Also known as primary yolk sac — per UBERON

The Parietal yolk sac is a part of the None.