Alimentary tract develops from primitive gut except a small cranial part developing from stomodeum and a small caudal part developing from proctodeum. Lining epithelium of alimentary tract develops from endoderm of primitive gut: while rest of the layers develops from splanchnopleuric intra embryonic mesoderm. Primitive gut is divided into foregut, midgut and hindgut. Foregut: Foregut gives rise to following parts of alimentary tract. Part of oral cavity, pharynx, oesophagus, stomach and part of duodenum up to opening of bile duct. Respiratory diverticulum arises from foregut which form the respiratory tract (both extra pulmonary and intra pulmonary). Liver and pancreas develop from buds arising at the junction of foregut and midgut. Artery of the foregut is celiac trunk. Midgut: The midgut gives rise to. The part of duodenum distal to opening of bile and pancreatic duct, small intestine, caecum and appendix, ascending colon and right two third of transverse colon. The artery of midgut is superior mesenteric artery. Hindgut: The hindgut gives rise to. Left one-third of transverse colon, descending colon, sigmoid colon, rectum and upper part of anal canal (up to pectinate line). The artery of hindgut is inferior mesenteric artery. Liver: The liver develops from hepatic diverticulum and septum transversum. Pancreas: The pancreas develops from dorsal and ventral pancreatic buds, which arise at the junction of foregut and midgut. Caecum and appendix: Caecal bud is a conical diverticulum that arises from post arterial segment of mid gut loop close to its apex. Proximal dilated part of caecal bud forms the caecum; while distal conical part of the caecal bud forms the appendix. Spleen: The spleen develops from mesodermal cells in dorsal mesogastrium. When the spleen develops in dorsal mesogastrium the dorsal mesogastrium is divided in two parts-gastrosplenic ligament and lienorenal ligament.