Pancreas
. Pancreas, conglomerate gland lying transversely across the posterior wall of the abdomen. It varies in length from 15 to 20 cm (6 to 8 in) and has a breadth of about 3.8 cm (about 1.5 in) and a thickness of from 1.3 to 2.5 cm (0.5 to 1 in). Its usual weight is about 85 gm (about 3 oz), and its head lies in the concavity of the duodenum. The pancreas has both an exocrine and an endocrine secretion. The exocrine secretion is made up of a number of enzymes that are discharged into the intestine to aid in digestion. The endocrine secretion, insulin , is important in the metabolism of sugar in the body (see Sugar Metabolism ). Insulin is produced in small groups of especially modified glandular cells in the pancreas; these cell groups are known as the islets of Langerhans. The failure of these cells to secrete sufficient amounts of insulin causes diabetes (see Diabetes Mellitus ). Diseases of the pancreas are not common. Hemorrhage in the pancreas and acute pancreatitis are, however, seri