Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to chorioallantois: chorioallantoic
an extraembryonic structure formed by union of the chorion and allantois, which by means of vessels in the associated mesoderm serves in gas exchange; in many mammals, it forms the placenta. adj., adj chorioallanto´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
Extraembryonic membrane formed by the fusion of the allantois with the serosa or false chorion. In mammalian embryos, it forms the fetal portion of the placenta; in avian embryos, it is fused with the shell.
Farlex Partner Medical Dictionary © Farlex 2012
The highly vascular fetal membrane that consists of the fused chorion and allantois, found adjacent to the eggshell in reptiles and birds and constituting the placenta in most mammals.
cho′ri·o·al′lan·to′ic (-ō-ăl′ən-tō′ĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
Extraembryonic membrane formed by the fusion of the allantois with the serosa or false chorion. In mammals it forms the fetal portion of the placenta; in avian embryos it is fused with the shell.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012