Digestive Diseases Glossary of Terms

Medically Reviewed by Sabrina Felson, MD on November 09, 2022
6 min read

These are common terms and definitions associated with the gastrointestinal system and digestive problems or diseases.

Abscess: A swollen, infected, pus-filled pocket that can develop anywhere in your body. In your digestive system, one way you could get them is if inflammation destroys and moves into the wall of your intestines. This happens sometimes with digestive conditions like Crohn’s disease

Amylase: Enzyme produced in the pancreas and salivary glands that helps in the digestion of starches from the diet. Blood amylase levels may be increased in patients who have pancreatitis or salivary problems like Sjogren’s disease.

Anal fissure: A crack or split in the skin around the anus that can cause pain, itching, and bleeding.

Amyloidosis: A group of diseases that results from the abnormal deposition of a protein called amyloid in tissues and organs.

Bezoar: A clump of food or hair that collects in the digestive tract. Bezoars can cause obstructions in the stomach that keep food from passing into the small intestine. 

Celiac disease: A disease resulting from the abnormal reaction by the body's immune system to gluten, a protein found in grains such as wheat, rye, and barley and other foods. In people who have celiac disease, the immune system causes damage to the small intestine and prevents the proper absorption of nutrients from food. Symptoms include diarrheaanemia, and weight loss.

Colon: The part of the large intestine that absorbs water from food waste to form stool. The word colon is also sometimes used as another general term for the large intestine (see definition below).

Colonoscopy: A procedure your doctor will do to view your colon. The doctor inserts a narrow tube with a camera at the tip into your rear end to examine your large intestine and the last part of your small intestine for signs of illness, inflammation, or abnormality.

Colostomy: A surgeon creates a hole, or “stoma,” in the skin of your lower belly and attaches part of your colon. Digestive waste then collects through the hole into a bag that is attached to you, which you empty and reattach. It may be temporary or permanent.

Crohn’s disease: This chronic condition inflames and irritates your digestive tract. It typically affects your small intestine or the start of your large intestine (colon), but it can attack any part of your digestive system, from your mouth to your anus. Crohn’s is one of the two main types of inflammatory bowel disease (IBD), along with ulcerative colitis.

Duodenum: The first part of the small intestine.

Elastase: An enzyme found in fluids produced by the pancreas. It aids in the digestion of several proteins, including elastin, an elastic substance in the lungs and other organs that is part of their structural framework. Normally, elastase is inhibited by a substance called alpha-1 antitrypsin.

Endoscopy: A procedure that uses a flexible, lighted tube to look inside the body. The instrument is introduced into the body through a natural opening like the mouth or anus.

Endoscopic ultrasound (EUS): A procedure that combines endoscopy and ultrasound and allows a doctor to obtain images and information about the digestive tract and the surrounding tissue and organs.

Endoscopic retrograde cholangiopancreatography (ERCP): Procedure in which a tube is placed down the patient's throat, into the stomach, then into the small intestine. Dye is injected and the ducts of the gallbladderliver and pancreas can be seen on X-ray. The procedure may be performed to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas, including gallstones, inflammatory strictures (scars), leaks (from trauma and surgery), and cancer.

Fistula: Inflammation passes through the wall of your intestines to form these abnormal passages or tunnels between two organs, or two parts of the same organ (like your intestines) that aren’t normally connected. A fistula can also tunnel through to the outside of your body.

Gastrin: A hormone that causes the stomach to produce acid, too much of which can cause stomach and duodenal ulcers.

Gastrinoma: Tumor that develops in the pancreas or duodenum. It can be associated with Zollinger-Ellison syndrome. Gastrinomas secrete the hormone gastrin.

Gastroesophageal reflux: A condition in which stomach acid and contents back up into the  esophagus, producing symptoms of heartburn or regurgitation.

Gastroparesis: Full or partial paralysis of the stomach. It is a disease in which the stomach cannot empty itself of food in a normal fashion. This can happen in diabetes.

H2 blockers: A group of digestive disease drugs that relieve acid reflux and pain by suppressing the production of stomach acid.

Hemorrhoid: Enlarged or swollen vein within or around the anus or rectum.

Hemorrhoidectomy: Surgery to remove hemorrhoids.

Hepatitis: A disease that infects your liver and causes it to become inflamed. There are five different types of hepatitis, and various causes of the disease, including alcohol use. 

HIDA scan: Also called cholescintigraphy, during this test a radioactive material, called hydroxy iminodiacetic acid (HIDA), is injected into the patient. The test is used to diagnose certain conditions of the liver and gallbladder.

Ileum: The last section of the small intestine. It connects to the colon (large intestine).

Jaundice: A yellowing of the skin and whites of the eyes that occurs when levels of the pigment bilirubin are abnormally high. This may occur when the liver is not working properly or when a bile duct is blocked.

Jejunostomy tube: A feeding tube that is inserted in a surgical procedure through the abdomen into the part of the small intestine called the jejunum. Nutrients are put into the tube to feed the patient who is unable to swallow.

Laparoscopic surgery: "Minimally invasive" surgery in which small (usually 5- to 10-millimeter) incisions are made. The laparoscope and surgical instruments are inserted through these incisions. The surgeon is guided by the laparoscope, which transmits a picture of the internal organs on a monitor.

Large intestine: The last part of your small intestine (ileum) connects to your large intestine. It’s where your body changes food waste from liquid to more solid form (fecal matter). The large intestine includes your colon, rectum, and anal canal. It’s about 5 feet long in most adults. 

Lipase: Enzyme produced in the pancreas and secreted into the small intestine that aids in the digestion of certain fats from food.

Liver function tests (LFTs): Also known as hepatic enzymes or liver blood tests, they can show evidence of conditions affecting the normal functioning of the liver, gallbladder or bile ducts.

Pancreatitis: Inflammation of the pancreas.

Parenteral nutrition: A feeding method in which nutrients go directly into the bloodstream through a catheter placed into a vein.

Proton pump inhibitors: Drugs that suppress acid production in the stomach.

Sclerotherapy: A procedure in which a chemical irritant solution is injected into a vein to sclerose, or harden it by causing scar formation. This forces blood flow to nearby healthy blood vessels. Sclerotherapy may be performed to treat hemorrhoids, esophageal varices, and varicose and spider veins.

Secretin: A hormone made in the small intestines that aids in digestion.

Secretin stimulation test: Test that measures the ability of the pancreas to respond to the hormone secretin.

Small intestine: The first section of the intestines that leads to the large intestine. It helps digest food and absorb nutrients from the stomach, before sending the waste on to the large intestine. It has three parts: The duodenum (upper part, closest to stomach), the jejunum (middle part), and the ileum (final part that connects to large intestine). 

Ulcerative colitis: Ulcerative colitis is one of the two main types of inflammatory bowel disease (IBD). The other is Crohn’s disease. Ulcerative colitis is a long-term condition that inflames and irritates the large intestine (colon), causing sores (ulcers) on the inner lining.

Ultrasound: The use of high-frequency sound waves to produce images of the organs and structures inside the body.

Vagus nerve: Also called cranial nerve ten, the vagus nerve regulates the function of numerous organs of the body from the throat and voice box to the trachea (windpipe), lungs, heart, and most of the intestinal tract. It also brings sensory information to the brain from the ears, tongue, and throat.

Villi: Hair-like structures that line the small intestine and absorb nutrients from food.

Zollinger-Ellison syndrome: A rare disorder of the gastrointestinal system caused by a tumor called a gastrinoma. Gastrinomas most often occur in the pancreas. The tumor secretes the hormone gastrin, which increases acid levels in the stomach, leading to severe, recurrent ulcers of the esophagus, stomach, and intestines.