extraembryonic membrane

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Related to extraembryonic membrane: extraembryonic mesoderm

ex′traembryon′ic mem′brane

any of the membranes derived from embryonic tissue that lie outside the embryo, as the allantois, amnion, chorion, and yolk sac.
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References in periodicals archive ?
The CAM is an extraembryonic membrane which serves as a gas exchange surface and its function is supported by a dense capillary network.
It begins with fertilization and implantation of the blastocyst into the uterine wall, followed by development of the extraembryonic membrane which gives rise to the placenta, which is, literally, the lifeblood of the fetus.
On the other hand, because salamander embryos contain pluripotent cells they had the raw material to evolve completely new structures such as extraembryonic membranes, which are fundamental to the development of reptiles and mammals.