The term "gastrointestinal" refers to the body’s stomach and intestines, which are parts of the digestive system. Along with other organs in the digestive system, these parts of the body aid in the digestion of food and the elimination of waste.
Once food and liquid pass through the mouth and the esophagus, they reach the stomach, where three distinct actions occur. First, the stomach stores the food and liquid consumed, and it's able to expand in order to do so. Second, it produces digestive juices and mixes them with the food and liquid to begin the digestion process. Finally, the stomach slowly releases the digested material into the small intestine.
Once in the small intestine, digestion of these materials continues. Juices from the liver, pancreas and intestine aid in this process. At this stage, the digested nutrients pass through the intestinal walls, where they enter the bloodstream and travel throughout the body. Other portions of the digested material continue through the intestinal tract as waste. The waste passes from the small intestine to the large intestine and ultimately is removed from the body with a bowel movement.
A wide variety of problems can affect the gastrointestinal tract. They range from mild annoyances like flatulence or acid reflux to life-threatening conditions like stomach or colon cancer. Some people develop inflammatory bowel diseases such as ulcerative colitis or Crohn’s disease, which cause symptoms such as abdominal pain and diarrhea. Ulcers are another problem that can frequently impact the stomach, and constipation is also commonly related to problems in the gastrointestinal tract. Treatment for gastrointestinal problems vary widely, depending on the cause and severity of the problem.
SOURCES: U.S. National Cancer Institute; U.S. National Institute of Diabetes and Digestive and Kidney Diseases