Sphincter of pancreatic duct

The sphincter of the pancreatic duct is a smooth muscle structure that surrounds the terminal portion of the pancreatic duct as it enters the duodenum, at the major duodenal papilla.

Its primary role is to regulate the flow of pancreatic juice (containing digestive enzymes and bicarbonate) into the duodenum, and to prevent reflux of duodenal contents into the duct. It operates in coordination with the sphincter of Oddi and the biliary system in species where these ducts converge.