The small intestine (or small bowel) is the part of the GI tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. The small intestine is composed of a duodenum, jejunum, and ileum. It receives bile juice and pancreatic juice through the pancreatic duct, controlled by the sphincter of Oddi. This article is primarily about the human gastrointestinal tract. The information about its processes is directly applicable to most placental mammals. The primary function of the small intestine is the absorption of nutrients and minerals found in food. A major exception to this is cows; for information about digestion in cows and other similar mammals, see ruminants. In invertebrates such as worms, the terms “gastrointestinal tract” and “large intestine” are often used to describe the entire intestine.