BIO 1130 Lecture Notes - Lecture 6: Yolk Sac, Allantois, Amniote
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BIO 1130 Full Course Notes
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Found in the hair, horns, nails, claws and hooves of mammals. Mammals, birds and reptiles (tetrapods) inherit amniote egg so that they don"t have to go back to the water to lay eggs. Amniote egg is a water filled sac that serves as a cushion and provides aqueous environment for embryo to grow. Consists of four membranes: the amnion, allantois, chorion, and yolk sac. The allantois collected nitrogenous waste so that it doesn"t poison the organism. The chorion provides oxygen and disposes of carbon dioxide. The yolk sac either provides yolk as nourishment or only stores the nutrients. Albumen is the egg white that fills the space. An organ that develops in mammals (except marsupials and monotremes) during pregnancy, joining the mother and offspring. Allows for release of carbon dioxide and waste products. Fuse together to form central shaft (the long hard part in the single feather that the hairs come off of)
