The pancreas is an organ that lies parallel to and beneath the stomach and that is a major contributor to the overall digestive process. The pancreas has both endocrine and exocrine functions. The exocrine portion of the pancreas consists of clusters of cells known as acini that make up lobules separated by connective tissue. These cells constitute almost 80% of the organ. An acinus consists of up to 50 cells that have a common orientation toward a central lumen. Each acinus is drained by a ductule.