Pancreas lobes, coloured scanning electron micrograph (SEM). Several lobes of the pancreas are seen here, separated by fissures. The smaller sections seen on each lobe are clusters of acini cells. These are exocrine cells, secreting digestive enzymes. The enzymes drain into a highly branched system of ducts of increasing size, that terminates in the main pancreatic duct, which feeds into the duodenum (small intestine). The other function of the pancreas is the endocrinal secretion of hormones, in particular insulin. Fragments of connective tissue and blood vessels are also seen.