Embryonic Folding

Upon completing the module, you should be able to answer the following questions: How does embryonic folding give rise to a cylindrical embryo from a trilaminar germ disc? Along what axis does folding occur? Where do specific tissues of the embryo, e.g., ectoderm, mesoderm, and endoderm come to lie after folding? How do these layers relate to their extraembryonic counterparts before and after folding? What are the general regions of the digestive (gut) tube? Which is connected to the yolk sac? The vitelline duct? What forms the umbilical cord? What are the two layers of lateral plate mesoderm, and what do they form? How are structures repositioned during cranial folding? How are structures repositioned during caudal folding? Where is the allantois formed? What is the original shape of the intraembryonic coelom, and what is it connected to? How does this change during folding? What lines the intraembryonic coelom? What is suspended by dorsal mesentery in the thorax? In the ab