The pancreas has both endocrine and exocrine functions. The exocrine pancreas is made up of pancreatic acinar cells and a duct system that opens into the proximal duodenum on the major duodenal papilla. Pancreatic acinar cells synthesize and secrete digestive enzymes (amylase, lipase, and others) and inactive proenzymes of digestive enzymes (zymogens: trypsinogen, chymotrypsinogen, proelastase, prophospholipase, and others) that are essential for the digestion of dietary macronutrients, such as proteins, triglycerides, and complex carbohydrates.
The exocrine pancreas also secretes other essential substances, such as large amounts of bicarbonate, which buffers gastric acid; intrinsic factor, which is needed for cobalamin absorption; and colipase, which is an essential cofactor for pancreatic lipase.
