The midgut is the portion of the embryo from which most of the intestines are derived. After it bends around the superior mesenteric artery, it's called the "midgut loop". It originates from the foregut at the opening of the bile duct into the duodenum and continues through the small intestine and much of the large intestine until the transition to the hindgut about two-thirds of the way through the transverse colon. Structures in the adult midgut Duodenum (3rd and 4th parts) Jejunum Ileum… (More on Midgut)