Figure 1.

The components of the pancreas. The pancreas consists of endocrine cells localized within structures named the Islets of Langerhans, which contain multiple endocrine cell types including the β cells that secrete isulin, and the exocrine pancreas, which is composed of acinar calls and ductal structures. Pancreatic acinar cells form a basic structure called an acinus that surrounds a central lumen open to the duct system. Pancreatic acinar cells produce, store and secrete enzymes necessary for the digestion and absorption of food in the small intestine. Digestive enzymes are secreted through the apical membrane of the acinar cell into small intercalated ducts that are directly connected to increasingly larger intralobular ducts that join the main pancreatic duct. The main pancreatic duct joins the common bile duct just prior to the ampulla of Vater, where both pancreatic and liver products enter the small intestine. Blockage of the passage of materials through the ampulla of Vater, for example by the lodging of a bile stone or by the growth of a tumor, leads to increased pressure in the duct system and gives rise to acute pancreatitis.