EVERYDAY SCIENCE

Detailed explanation-1: -The allantois stores metabolic wastes (chiefly uric acid) of the embryo and, as it grows larger, also participates in gas exchange.

Detailed explanation-2: -The allantois serves as a respiratory organ and as a reservoir for the excreta. These temporary organs function within the egg until the time of hatching and form no part of the fully developed chick.

Detailed explanation-3: -allantois, an extra-embryonic membrane of reptiles, birds, and mammals arising as a pouch, or sac, from the hindgut. In reptiles and birds it expands greatly between two other membranes, the amnion and chorion, to serve as a temporary respiratory organ while its cavity stores fetal excretions.

Detailed explanation-4: -The allantois stores urinary waste, and helps with the exchange of gases in general, which makes it a crucial structure since it delivers oxygen to the embryo. It also has a very important role in egg-laying animals, including all birds, as it serves as the embryo’s respiratory organ together with the chorion.

Detailed explanation-5: -The allantois arises as an endodermally lined ventral outpocketing of the hindgut (see Figure 1). In the human embryo, it is just a vestige of the large, saclike structure that is used by the embryos of many mammals, birds, and reptiles as a major respiratory organ and repository for urinary wastes.