allantois

allantois definition - medical

al·lan·to·is (ə-lănˈtō-ĭs)

noun pl. al·lan·to·i·des (ălˌən-tōˈĭ-dēzˌ)
A membranous sac that develops from the posterior part of the alimentary canal in the embryos of mammals, birds, and reptiles, and is important in the formation of the umbilical cord and placenta in mammals. Also called allantoid.

Related Forms:

  • alˌlan·toˈic (ălˌən-tōˈĭk) adjective

The American Heritage® Medical Dictionary Copyright © 2009 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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