The pancreas is a glandular organ serving as the digestive system and endocrine system in vertebrates. It is narrow and 6-inch in length, located posterior and inferior to the stomach with the head lying immediately adjacent to the duodenum and the body and the tail extending across the midline nearly to the spleen. The pancreas is composed of endocrine and exocrine glandular tissue. The exocrine tissue accounts for about 99% of the pancreas by weight while endocrine tissue only accounts for 1%. Organized by many acini, the exocrine tissue is devoted to secreting digestive enzymes that are received by pancreatic ducts and transferred into the duodenum. Each acinus is arranged by a cluster of acinar cells that surrounds tiny ducts. Sit between the clusters of acinar cells are scattered endocrine tissue of the pancreas, collectively known as the islets of Langerhans. Alpha cells and beta cells consist of the two main types of the islets. The two hormones glucagon and insulin secreted by islets play an essential role in regulating the blood glucose levels. The pancreas may be the site of acute and chronic infections, cysts and tumors. A variety of target molecules are used to detect associated disorders.