Pancreas

Acini of the exocrine pancreas demonstrate the polarity of exocrine secretory cells.  Rough endoplasmic reticulum is evident at the periphery of each acinar cell; secretory granules are located at the apex, adjacent to the lumen into which their contents will be released.  Centroacinar cells, located in the center of each acinus, form the beginning of the intralobular duct system.  400x

The acinar cells of the exocrine pancreas synthesize digestive enzymes in basally-located rough endoplasmic reticulum. The enzymes, in their inactive form, are packaged into secretory granules and then released into the duct system. The enzymes are not activated until they reach the lumen of the duodenum.

The acinar cells of the exocrine pancreas synthesize digestive enzymes in basally-located rough endoplasmic reticulum. The enzymes, in their inactive form, are packaged into secretory granules and then released into the duct system. The enzymes are not activated until they reach the lumen of the duodenum.

A unique feature of the exocrine pancreas is that the smallest duct (intralobular duct) begins with centroacinar cells located within the center of the acinus. Intercalated ducts transport bicarbonate and water into their lumens.