And not only that, but as the embryo actually develops our endodermal cells basically create algorithms that eventually form the accessory organs of our digestive system and that includes things like the liver, which forms the bile and the bile eventually stored inside the gallbladder. So the gallbladder is also formed from the endoderm germ layer and we form the pancreas because as we know the pancreas produces many of the digestive enzymes that are used by that digestive system. So essentially the entire digestive system, not including the mouth and the anus, is formed from the endoderm germ layer. So what else do we form? Well, the thyroid gland, the parathyroid gland and the thiamus gland. All these glands are essentially formed by the endoderm germ layer.