Pancreas is a mixed gland. It looks like a leaf or a cylinder or a drum or a pepper. This gland consists of three parts. Head, body and tail. In cellular structure it consists of two parts. Duct part or acinus and duct part or islets of Langerhans. Its length is 20 cm and width is 5 cm. Small ducts emerge from the pancreatic gland. These ducts join together to form the Wirsang duct. The Wirsang duct then enters the duodenum through the ampulla of Vater. Pancreas is divided into several segments called lobules. Between the lobules there are clusters of cells called islets of Langerhans. Islets of Langerhans are composed of about 1 million cells. It contains four types of cells. Alpha, Beta, Gamma and Delta. The pancreas secretes 500-1200 ml of juice every 24 hours. It is colorless, alkaline and liquid. Its pH is 7.5-8.5.