WordNet-Online
Free dictionary and thesaurus of English. Definitions, synonyms, antonyms and more...
Hint: double-click any word to get it searched!

	Enter your search terms Submit search form
	Web www.wordnet-online.com

Definitions from WordNet

Definitions from the Web

Definition: The embryonic membrane in reptiles, birds, and mammals that functions as a respiratory organ and contributes to waste management and nutrient transfer.

Sample sentences:

Noun - Sense 1: The allantois in reptiles serves as a conduit for the exchange of gases between the embryo and the mother's bloodstream.

"The allantois in a snake embryo allows for efficient oxygen supply during development."

Noun - Sense 2: The allantois in birds is responsible for storing waste materials produced by the embryo.

"During incubation, the allantois in birds accumulates uric acid, which gets expelled upon hatching."

Noun - Sense 3: In placental mammals, the allantois extends from the embryo, forming the fetal part of the placenta.

"The allantois undergoes extensive growth in mammals, playing a crucial role in nutrient and waste exchange with the mother."

Related products: - Allantois in Biology Books - Allantois Embryology Textbooks - Allantois Respiration Equipment