BIOL 204 Lecture 3: Lecture 3
Document Summary
Formation of the coelom in the chick: solid sheet of hypomere mesoderm splits into 2 layers, somatic hypomere, splanchnic hypomere, creates a space- coelom. In mammals, the muscular diaphragm separates the pleuroperitonal cavity into 2 separate cavities: pleural cavity, contains the lungs, peritoneal cavity, contains the viscera (except for heart and lungs) In birds, crocodilians, turtles, and some lizards, a thin and non-muscular post- pulmonary septum separates the pleuroperitoneal cavity into the pleural cavity and peritoneal cavity. Organogenesis: embryo continues to grow, each of the 3 embryonic germ layers continue to differentiate. Extra-embryonic membranes: extra-embryonic membranes: amnion, chorion, allantois, and yolk sac, extra-embryonic membranes are produced by the embryo. They grow outward from the embryo: only amniotes have an amnion, chorion, and allantois, amniotic folds- start of development of extra amniotic membranes. Extra-embryonic membranes- functions: allantois sequesters nitrogenous metabolic wastes away from the embryo, toxic, the yolk sac grows ventrally to surround the yolk and forms blood vessels called.
