Light microscopy of the pancreas. Most (>95%) of the pancreas is comprised of branching glands that synthesize digestive enzymes stored in the cells as compacted clusters of granules (pink). Upon release these enzymes enter a duct system that empties into the duodenum. The large aggregations of pale pink cells are called islets of Langerhans and produce pancreatic hormones such as insulin and glucagon which are released into the bloodstream. Magnification x100 when printed at 10 cm.