A long, thin organ in humans, the pancreas has both digestive and endocrine functions and for this reason contains two completely different types of cells. Measuring about 12-15 cm (5-6 in) long. It is nestled within the curve of the duodenum and stretches transversely across the posterior abdomen behind the stomach, in front of the spine and aorta. The digestive, or exocrine, cells of the pancreas consist of a number of small lobules, or acinar cells, joined together into small ducts that, in turn, join the two major ducts of Santorini and Wirsung, which empty through small muscular openings into the duodenum. The lobules contain numerous cells that secrete pancreatic secretions containing electrolytes and three important digestive enzymes, typsin, amylase, and lipase. These enzyme digest proteins, split fat, break down highly polymerized nucleic acids, and break down polysaccharides such as starch, amylopectin, and glycogen. The protein splitting enzyme enterokinase is mixed with it,...