It is a short stretch of about ten inches that receives sterilized and partly digested food from the stomach , pancreatic juice from the pancreas , and bile from the liver and gallbladder. Role When partly digested food products first enter the small intestine, they are bathed in enzymes from the pancreas and liver as well as those from the stomach . As nutrients become broken into small enough molecules, they are able to pass through projections in the walls of the jejunum and ileum into the blood . The upper portion of the small intestine, the duodenum, is subject to ulcers that are similar to those in the stomach and that are probably also caused by bacterial action that allows the strong enzymes and acids of those parts of the digestive system to attack the lining. Several disorders affect both the small and large intestines, including gastroenteritis , Crohn's disease, and diverticulosis.
Some hernias involve the small intestine.
The small intestine is subject to the disorders ileitis , ileus , and intussusception . There are also a number of congenital birth defects that involve the small intestine. Some parasites, including tapeworm , live primarily in the intestines.