Common bile duct, an excretory passage in the liver that releases a fat emulsifier, and a pancreatic duct, which releases pancreatic juice into the duodenum. The duodenum is cut away to show the major duodenal papilla and the texture of the interior of the duodenum. The liver, gallbladder, spleen, small intestine, and abdominal aorta are also visible. The common bile duct and the main pancreatic duct merge just outside the duodenum, the beginning of the small intestine, at the hepatopancreatic ampulla.