X rays of the small intestine taken as barium liquid passes through the organ. Also called small bowel follow-through.

The organ where most digestion occurs. It measures about 20 feet and includes the duodenum, jejunum, and ileum.

The standard test for diagnosing celiac disease.

A rare type of ulcer in the rectum that can develop because of straining to have a bowel movement.

A hormone in the pancreas that helps the body know when to make the hormones insulin, glucagon, gastrin, secretin, and renin.

Muscle movements, such as those in the colon, that cause pain, cramps, and diarrhea.

Tissue in an organ such as the mouth or esophagus that consists of layers of flat cells.

A condition in which the body cannot absorb fat. It causes a buildup of fat in the stool and loose, greasy, and foul-smelling bowel movements.

The buildup of fat in liver cells, commonly caused by alcoholism. Other causes include obesity, diabetes, and pregnancy. Also called fatty liver.

A ringlike band of muscle that opens and closes an opening in the body. An example is the muscle between the esophagus and the stomach known as the lower esophageal sphincter.