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extraembryonic membranes

The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in vertebrates, such as reptiles; birds; and mammals. They are the yolk sac, the allantois, the amnion, and the chorion. These membranes provide protection and means to transport nutrients and wastes.
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Entry Terms:
  • extra-embryonic membranes
  • foetal membranes
  • fetal membranes
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RDF/XMLCreated 2006-01-19, last modified 2013-09-05