The Islets of Langerhans, named "islets" because of their globular shape, and "of Langerhans" from the researcher who first described them, are endocrine glands located inside the pancreas. (Unlike the rest of the pancreas, their output is not to the digestive tract but only into the blood.) They produce insulin, a hormone whose function is to reduce the blood sugar level when it becomes too high, by triggering in the liver and muscles the conversion of circulating sugar to stored glycogen (aka "animal starch").