And this green layer which is found on the inside will form our digestive system. It will form the epithelial layer of our digestive system as well as the lungs, the liver, the pancreas and the bladder. Now this structure develops into the umbilical vesicle. This entire structure is the corianic cavity and this outside portion is the coriane. This extension is what becomes our placenta. This structure here that connects the placenta, the corian, to the growing embryo is the embryonic stock.