Oppenheimer, Steven B. Department of Biology, California State University, Northridge, California.
- Chick embryo
- Blood circulation
- Red blood cell production
- Role in immune system
- Primordial germ cell origin
- Related Primary Literature
- Additional Reading
An extraembryonic membrane which extends through the umbilicus in vertebrates. In some elasmobranchs, birds, and reptiles, it is laden with yolk which serves as the nutritive source of embryonic development. Developed in the splanchnopleure, it is composed of an endodermal layer and a mesodermal layer in which blood vessels are formed. See also: Germ layers
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