Pancreatic islets are some islet-like structures of cells present in the pancreatic tissue, which mainly secrete insulin and have the function of regulating blood sugar. The pancreas is a very important digestive and secretory organ in the human body. Its secretion is divided into two parts: 1) exocrine secretion, which produces digestive enzymes, amylase, lipase and protease, and the food eaten is digested and metabolized by these enzymes secreted by the pancreas; 2) another part of the cells of the pancreas produces insulin and glucagon, which directly enter the blood to regulate blood glucose. It is not normal to have too much or too little insulin. Insufficient function of the pancreas or reduced insulin secretion will produce diabetes, which is very common nowadays. If the pancreatic islets are overactive, they can also grow tumors, i.e. insulinomas, and too much insulin can cause hypoglycemia, which is also very dangerous.