allantois
- noun
- /əˈlæn.təʊ.ɪs/
- Specialized
:
alantoides
- Furthermore, the zygote-formed embryos are enveloped by the yolk sac (this part does not develop in the human fetus), amnion, allantois, and chorion.
Examples
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The allantois serves as a vital organ for gas exchange in the developing embryo.
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As the bird embryo develops, the allantois forms a network of blood vessels for oxygen supply.
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In reptiles, the allantois plays a crucial role in waste removal as the embryo grows.
Surface Forms
Morphology
allantois = allanto + is
A technical anatomical term built from a Greek combining form 'allanto-' plus a Greek noun ending '-is'; the components are not productive or recognizable to typical learners, so the meaning cannot be derived from English base words.
Etymology
Allantois comes from the Greek word allantos, which means 'sausage', because this membrane looks like a small sausage or sac in the embryo. That's why the allantois is a sac-like membrane that helps with gas exchange and waste removal during development.
