An extensive expanding ductal system collects secretions from the lobules and carries it to common pancreatic ducts. Prior to reaching the upper duodenum, the common pancreatic duct join with the common bile duct then empties into the duodenum at the sphincter of Oddi. Bicarbonate or aqueous component - functions to neutralize stomach acid. The proteolytic enzymes of the pancreas are synthesized in an inactive form - trypsinogen, chymotrypsinogen, procarboxypeptidase. These enzymes are activated in the intestine by enterokinase which is secreted by the intestinal mucosa.
Trypsin can, when activated, activate the other inactive enzymes.
Enzyme containing granules are expelled by exocytosis following a stimulus. Acinar cells also secrete a trypsin inhibitor which prevents activation of trypsin prematurely within the ducts. D. Regulation of Pancreatic Secretion 1. Secretin primarily stimulates luminal cells to secrete bicarbonate. Cholecystokinin stimulates enzyme secretion from acini.