Structural organization of the exocrine pancreas.
A. The pancreas has two components: the endocrine pancreas composed of the islets of Langerhans and the exocrine pancreas made up of branched lobules that drain their contents into the duodenum. B. Organization of the acinar and centroacinar cells in one of the lobules. C. Polarized structure of a pancreatic acinar cell. Rough endoplasmic reticulum (RER) in the basal region synthesizes digestive enzymes, which are packaged into zymogen granules that accumulate in the apical region ready for release. Thin strands of endoplasmic reticulum (ER) extend down into the apical region where they have channels that release pulses of Ca2+ to control secretion. Regulation of secretion is described in Module 7: Figure control of pancreatic secretion.