The digestive system consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus. These organs work together to perform the process of digestion. Digestion breaks down large food particles into smaller ones which are absorbed through the lining of the intestines into the bloodstream, carried to cells and used for energy. Digestive diseases and disorders interfere with this process, creating symptoms such as bloody stools, diarrhea, constipation, abdominal pain and unintended weight loss.
Colonoscopy
A colonoscopy is used to find inflamed tissue, abnormal growths and ulcers of the colon, or large intestine. To perform this test, a colonoscope equipped with a small camera is inserted through the anus into the colon. This test can produce a picture of the entire length of the large intestine, which includes the colon and rectum.
Upper GI Series
The upper GI series of tests utilizes X-rays along with barium, a metallic element that appears white on X-rays. To perform this test, the patient must drink a solution containing barium; this will coat the lining of the digestive tract and make any disease or abnormality easier to see. A series of X-rays, or X-ray video known as fluoroscopy, are taken as the liquid moves through the digestive system. Merck.com reports that barium can show abnormalities such as ulcers, tumors, obstructions, erosions and dilated esophageal veins.
Lower GI Series
The lower GI series test is similar to the upper GI series in that it uses X-rays with the help of barium to detect abnormalities. In this test, however, the barium is given as an enema, meaning it is inserted through the anus. This allows visualization of the large intestine, also called the colon, rectum and anus. A lower GI series detects the presence of polyps, bulges in the intestinal wall known as diverticula, cancerous growths, ulcers and inflammation, according to the National Digestive Disorders Information Clearinghouse. In addition, a lower GI series can detect fistulae, openings in the intestinal wall that allows waste to leak into the abdominal cavity.
Upper Endoscopy
An upper endoscopy utilizes an endoscope, a flexible tube used to visualize internal organs, inserted through the mouth to view the esophagus, stomach and duodenum, or the upper portion of the small intestine. This diagnostic test is useful when the patient is experiencing abdominal pain, nausea, vomiting, difficulty swallowing, acid reflux, unexplained weight loss and anemia. An upper endoscopy detects the presence of stomach ulcers, abnormal growths, inflammation of the upper digestive tract and hiatal hernias, according to the National Digestive Diseases Information Clearinghouse.
