Changes in Duct and Vascular Permeability: The Key to the Development of Acute Pancreatitis

The pancreatic duct acts like a semipermeable membrane, restricting the passage of various molecules through it in both directions. Among other factors, the size of the molecule determines the ease with which that passage takes place. Relatively small particles, like bicarbonate and chloride ions, diffuse through the duct wall easily. Normally, large molecules like the pancreatic digestive enzymes are contained within the duct almost entirely.