Islets can be found in many regions of the pancreas, but are especially numerous in the tail. Note that they are composed of clusters of cells. You will NOT be held responsible for light microscopic identification of these cell types within the islet . Although three or four cell types can be found in human islets, special methods are necessary to demonstrate them. In this preparation they have uniformly eosinophilic cytoplasm.
Delta cells are more difficult to demonstrate.
This thin section of pancreas shows less shrinkage of the cells but you will still not be able to distinguish cell types within the islets. The crystalloid core of beta cell granule contents can be a useful marker for beta cells when viewing EM of several cell types in the pancreatic islet. The general organization of the adrenal is apparent in this preparation, and the morphology of the cells is well preserved. In some sections, an area of cortex may appear to be surrounded by medulla, but serial sections would reveal that this cortex area is continuous with the rest of the cortex. These cells form oval groups, 2-3 cells thick.