About ASGE

Gastrointestinal Glossary of terms

Full Glossary (pdf)




Area between the chest and the hips that contains the stomach, small intestine, large intestine, liver, gall bladder, pancreas, and spleen.

Failure of the lower esophageal sphincter, a valve that separates the stomach and the esophagus, to open.

Sudden onset of symptoms.

Developed after birth.

Ingestion of air.

Afferent nerves
Nerve fibers (usually sensory) that carry impulses from an organ or tissue toward the brain and spinal cord (central nervous system), or the information processing centers of the enteric nervous system, which is located within the walls of the digestive tract.

Absence of nerve cells.

Ambulatory care
Health services provided in a doctor's office, or on an outpatient basis.

Ambulatory Endoscopy Center (AEC)
Medical facility that performs endoscopy procedures.

Amino Acids
A group of 20 different kinds of small molecules that link together in long chains to form proteins. Often referred to as the "building blocks" of proteins.

Anal fissure
A cut in anal canal.

Anastomosis, intestinal
Reattachment of two portions of bowel together.

Drugs that inhibit smooth muscle contraction in the gastrointestinal tract.

The opening of the rectum.

Autonomic nervous system
The part of the nervous system that controls involuntary actions of internal organs such as the bowel.






A metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray.

Basic science
The fundamental approach to understanding how systems work. Basic research takes place in the laboratory and often involves the study of molecules and cells.

Secretions of the liver that aid in digestion and absorption, and stimulate peristalsis.

Biliary tract
Gall bladder and the bile ducts.

Biomedical model
The model of illness and disease in Western medical education and research. It has two assumptions: (1) reductionism - that all conditions can be linearly reduced to a single cause, and (2) dualism - where illness and disease are divided either to an "organic" disorder having an objectively defined cause, or a "functional" disorder, with no specific cause or pathophysiology. The biomedical model is not sufficient to explain the functional GI disorders.[Rome II]

Tissue sample.

Biopsychosocial model
A model that proposes that illness and disease result from simultaneously interacting systems at the cellular, tissue, organismal, interpersonal, and environmental level. It incorporates the biologic aspects of the disorder with the unique psychosocial features of the individual, and helps explain the variability in symptom expression among individuals having the same biologic condition.

A process in a clinical study that conceals a treatment from the patient and/or investigator.

Audible rumbling abdominal sounds due to gas gurgling with liquid as it passes through the intestines.

The intestines.

Brain-gut axis
The continuous back and forth exchange of information and feedback that take place between the gastrointestinal tract, and the brain and spinal cord (which together comprise the central nervous system).






Capsule Endoscopy
A procedure that lets your doctor examine the lining of the middle part of your gastrointestinal tract, which includes the three portions of the small intestine (duodenum, jejunum, ileum). Your doctor will use a pill sized video capsule called which has its own lens and light source and will view the images on a video monitor. You might hear your doctor or other medical staff refer to capsule endoscopy as small bowel endoscopy, capsule enteroscopy, or wireless endoscopy.

Celiac disease
An allergic reaction of the lining of the small intestine in response to the protein gliadin (a component of gluten). Gliadin is found in wheat, rye, barley, and oats. Celiac disease is also called celiac sprue, and gluten intolerance.

The basic unit of any living organism. It is a small, watery, compartment filled with chemicals and a complete copy of the organism's genome.

Symptoms occurring over a long period of time.

Clinical significance
A conclusion that an intervention has an effect that is of practical meaning to patients and health care providers.

Clostridium difficile (C. difficile)
A gram-positive anaerobic bacterium. C. difficile is recognized as the major causative agent of colitis (inflammation of the colon) and diarrhea that may occur following antibiotic intake.

Cohort study
An observational study in which outcomes in a group of patients that received an intervention are compared with outcomes in a similar group i.e., the cohort, either contemporary or historical, of patients that did not receive the intervention.

Removal of part or the entire colon.

Inflammation of the colon.

The large intestine.

Colonoscopy is a fiberoptic (endoscopic) procedure in which a thin, flexible, lighted viewing tube (a colonoscope) is threaded up through the rectum for the purpose of inspecting the entire colon and rectum and, if there is an abnormality, taking a tissue sample of it (biopsy) for examination under a microscope, or removing it.

A surgically created opening of the colon to the abdominal wall, allowing the diversion of fecal waste.

Conditions existing at birth, but not through heredity.

Contrast radiology (GI)
A test in which a contrast material (i.e., Barium) is used to coat the rectum, colon, and lower part of the small intestine so they show up on an x-ray.

(See Randomized controlled trial) A standard of comparison which can be a conventional practice, a placebo, or no intervention.

Control group
A group of patients that serves as the basis of comparison when assessing the effects of the intervention of interest that is given to the patients in the treatment group.

Reduced stool frequency, or hard stools, difficulty passing stools, or painful bowel movements.

A hormone associated with the physical effects of the stress response within the body.

Crohn's disease
A form of inflammatory bowel disease.

A type of protein released by cells of the immune system, which act through specific cell receptors to regulate immune responses.






An excessive loss of fluids in the body.

A disease in which blood glucose (blood sugar) levels are above normal. Type 2 diabetes, also known as adult-onset or noninsulin-dependent diabetes mellitus (NIDDM), is the most common form of diabetes.

The muscle wall between the chest and the abdomen.

Passing frequent and loose stools that can be watery. Acute diarrhea goes away in a few weeks, and becomes chronic when it lasts longer than 4 weeks.

Expansion of an organ or vessel.

A disturbance in regular or normal function. An abnormal condition.

A swelling of the abdomen.

Occurs when a diverticulum become infected or irritated.

Diverticula (diverticulosis)
Small pouches in the colon.

Double blinding
A process in a clinical study that conceals the treatment from both the patient and the investigator.

The first part of the small intestine.

The sensation of food sticking in the esophagus






The extent to which an intervention does people more good than harm under general or routine conditions.

Efficacy The extent to which an intervention improves the outcome for people under ideal circumstances. Testing efficacy means finding out whether something is capable of causing an effect at all.

Efferent nerves
Nerve fibers that carry impulses away from the brain and spinal cord (central nervous system), which cause a muscle or gland to function.

Chemicals that break down into ions (atoms) in the body's fluids and are essential to regulating many body functions.

A thin, flexible tube with a light and a lens on the end used to look into the esophagus, stomach, duodenum, small intestine, colon, or rectum.

A procedure that uses an endoscope to diagnose or treat a condition. There are many types of endoscopy; examples include colonoscopy, sigmoidoscopy, gastroscopy, enteroscopy, and esophogogastroduodenoscopy (EGD).

Enteral nutrition
Food provided through a tube placed in the nose, stomach, or small intestine.

An irritation of the small intestine.

Inflammation of the intestines ganglion: A mass of nerve cells.

Examination of the inside of the small intestine using an endoscope.

Enteric nervous system (ENS)
Autonomic nervous system within the walls of the digestive tract. The ENS regulates digestion and the muscle contractions that eliminate solid waste.

Eosinophilic gastroenteritis
A rare disease characterized by food-related reactions, infiltration of certain white blood cells (eosinophils) in the GI tract, and an increase in the number of eosinophils in the blood.

The study of the distribution of health-related states or events in specified populations and the application of this study to the control of health problems.

The inner and outer tissue covering digestive tract organs.

An irritation of the esophagus.

The organ that connects the mouth to the stomach.

Esophagogastroduodenoscopy (EGD)
Examination of the inside of the esophagus, stomach, and duodenum using an endoscope. (Also called Gastroscopy or Upper Endoscopy)


Findings based on the use of current best evidence from scientific and medical research.






Failure to thrive (Pediatric)
A condition that occurs when a baby does not grow normally.

Tending to occur in more members of a family than expected by chance alone.

A hard mass of dried feces.

Waste eliminated from the bowels.

An abnormal passage between two organs or between an organ and the outside of the body.

5-hydroxytryptamine (5-HT)
See Serotonin.

Food allergy
An immune system response by which the body creates antibodies as a reaction to certain food. Studies show that true food allergies are present in only 1-2% of adults.

Functional disorder
A functional disorder refers to a disorder or disease where the primary abnormality is an alteration in the way the body works (physiological function). It characterizes a disorder that generally cannot be diagnosed in a traditional way; that is, as an inflammatory, infectious, or structural abnormality that can be seen by commonly used examination, x-ray, or blood test.






Related to the stomach.

Gastric Juices
Liquids produced in the stomach to help break down food and kill bacteria.

An inflammation of the stomach lining.

An infection or irritation of the stomach and intestines

A doctor who specializes in digestive diseases or disorders.

The field of medicine concerned with the function and disorders of the digestive system.

Gastrointestinal (GI) tract
The muscular tube from the mouth to the anus, also called the alimentary canal or digestive tract.

Nerve or muscle damage in the stomach leading to delayed gastric emptying.

Examination of the inside of the esophagus, stomach, and duodenum using an endoscope.

Gastrostomy (G-tube)
A method of enteral feeding in which a tube is surgically or endoscopically introduced through the abdominal wall.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

The complete genetic material of an organism.

GERD (gastroesophageal reflux disease)
Also called acid reflux, a condition where the contents of the stomach regurgitates (or backs up) into the esophagus (food pipe), causing discomfort and sometimes esophageal injury.

Glial cell
A type of cell that surrounds nerve cells and holds them in place. Glial cells also insulate nerve cells from each other.

Gluten intolerance
See Celiac disease.







A class of medicines that reduce the amount of acid the stomach produces.

Health related quality of life
The impact an illness has on quality of life, including the individual's perception of his or her illness.

Health-related quality of life (HRQL) measures
Patient outcome measures that extend beyond traditional measures of mortality and morbidity, to include such dimensions as physiology, function, social activity, cognition, emotion, sleep and rest, energy and vitality, health perception, and general life satisfaction. (Some of these are also known as health status, functional status, or quality of life measures.)

Helicobacter pylori (H. pylori)
A bacterium that can damage stomach and duodenal tissue, causing ulcers and stomach cancer.

Veins around or inside the anus or lower rectum that are swollen and inflamed.

Related to the liver.

Genetically transmitted or transmittable from parent to offspring.

The extent to which a trait is influenced by our genetic makeup.

Hiatal hernia
A small opening in the diaphragm that allows a part of the stomach to move up into the chest.

Lowered threshold to pain.

Increased vigilance. An intensified state of paying attention to or focusing on specific things. May severely limit a person's ability to focus on specific tasks or engage in reflective thinking when their focus is on scanning for threatening stimuli. A person with a functional GI disorder or incontinence may be hypervigilant when their focus is on scanning for bodily sensations or indications that signal symptom onset.






A surgically created opening of the abdominal wall to the ileum, allowing the diversion of fecal waste.

The lower third of the small intestine, adjoining the colon.

A subjective state of feeling unwell that may include impairment of normal physiological and social function.

Tests that produce pictures of areas inside the body.

Imperforate anus
A birth defect in which the anal canal fails to develop, treated surgically.

Describes the occurrence of a disease or disorder in a population. It is a rate, showing how many new cases of a disease occurred in a population (typically a susceptible population called the "at-risk population" ) during a specified interval of time (usually expressed as number of new cases per unit time per fixed number of people; e.g., number of new cases per 1,000 persons in one year).

Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.

Inflammatory bowel disease (IBD)
A set of chronic diseases characterized by irritation and ulcers in the gastrointestinal tract. The most common disorders are ulcerative colitis and Crohn's disease.

Taking into the body by mouth.

Transmitted through genes from parents to offspring.

Institutional review board (IRB)
In the U.S. a group of scientists, doctors, clergy, and consumers at each health care facility that participates in a clinical trial. IRBs are designed to protect study participants. They review and must approve the action plan for every clinical trial. They check to see that the trial is well designed, does not involve undue risks, and includes safeguards for patients.

Interstitial cells of Cajal (ICC)
Specialized pacemaker cells found throughout the gastrointestinal tract that are required for normal gastrointestinal motility.

Interstitial cystitis
A long-lasting condition also known as painful bladder syndrome or frequency-urgency-dysuria syndrome. The wall of the bladder becomes inflamed or irritated, which affects the amount of urine the bladder can hold and causes scarring, stiffening, and bleeding in the bladder.

A structure supplied with intact nerves.

Anything meant to change the course of events for someone (e.g., drug, surgery, test, treatment, counseling, etc.)

Intestinal mucosa
The surface lining of the intestines where the cells absorb nutrients.

Intestinal pseudo-obstruction
Symptoms and signs of intestinal blockage, but no actual blockage.

Also known as the bowels, or the long, tube-like organ in the human body that completes digestion or the breaking down of food. They consist of the small intestine and the large intestine.

Symptoms that don't respond to usual treatments.

In U.S. clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered investigational in other diseases or conditions. Also called experimental.

In vitro
In the laboratory (outside the body). The opposite of in vivo (in the body).

In vivo
In the body. The opposite of in vitro (outside the body or in the laboratory).

Ischemic colitis
Colitis caused by decreased blood flow to the colon.






Jejunostomy (J-tube)
A method of enteral feeding in which a tube is surgically placed in the small intestine.











Laboratory study
Research done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful. Laboratory studies take place before any testing is done in humans.

Laboratory test
A medical procedure that involves testing a sample of blood, urine, or other substance from the body. Tests can help determine a diagnosis, plan treatment, check to see if treatment is working, or monitor the disease over time.

A sugar found commonly in milk and dairy products.

Lactose intolerance
The inability to digest or absorb lactose.

The insertion of a thin, lighted tube (called a laparoscope) through the abdominal wall to inspect the inside of the abdomen and remove tissue samples.

Large intestine
The long, tube-like organ that is connected to the small intestine at one end and the anus at the other. The large intestine has four parts: cecum, colon, rectum, and anal canal. Partly digested food moves through the cecum into the colon, where water and some nutrients and electrolytes are removed. The remaining material, solid waste called stool, moves through the colon, is stored in the rectum, and leaves the body through the anal canal and anus.

A compound that increases fecal water content.

A type of white blood cell. Lymphocytes have a number of roles in the immune system, including the production of antibodies and other substances that fight infection and diseases.






A test that measures pressure or contractions in the gastrointestinal tract.

Mast cell
A type of immune system cell present in blood and tissue.

Mast cell degranulation
The release from within the cell of granules, or small sacs, containing chemicals that can digest microorganisms and activate other cells to fight infection.

Substances within the body, such as hormones, that can transmit messages to nerve or muscle tissue to stimulate a response.

A method of summarizing previous research by reviewing and combining results from multiple studies.

The movement of cells, etc. from one position to another.

A disease or the incidence of disease within a population. Morbidity also refers to adverse effects caused by a treatment.

Movement of content within the gastrointestinal tract.

Originating in muscle tissue.






Nasogastric tube (NG-tube)
A tube placed through a nasal passageway into the stomach.

Cells in the human body that are the building blocks of the nervous system (the system that records and transmits information chemically and electrically within a person). Nerve cells, or neurons, are made up of a nerve cell body and various extensions from the cell body that receive and transmit impulses from and to other nerves and muscles.

Having to do with nerves or the nervous system, including the brain and the spinal cord.

A member of a class of protein-like molecules made in the brain. Neuropeptides consist of short chains of amino acids, with some functioning as neurotransmitters and some functioning as hormones.

A chemical in the nervous system that helps transmit messages.

NIH or National Institutes of Health
The focal point of biomedical research in the United States. NIH conducts research in its own laboratories; supports the research of non-Federal scientists in universities, medical schools, hospitals, and research institutions throughout the country and abroad; helps in the training of research investigators; and fosters communication of medical information. Access the NIH Web site at http://www.nih.gov.

Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group. If human subjects are involved, they know what treatments they are receiving.

A chemical compound (such as protein, fat, carbohydrate, vitamins, or minerals) that make up foods.

The taking in and use of food and other nourishing material by the body.











P value
The p (probability) value is a calculation used in studies to determine if the results are caused by chance or not. The lower the p-value, the more likely it is that the difference between groups was caused by treatment. A p value less than 0.05 is statistically significant and indicates that the result is not due to chance.

Pain threshold
The point at which a person becomes aware of pain.

Examination by pressing on the surface of the body to feel the organs or tissues underneath.

Parenteral nutrition
The slow infusion of a solution of nutrients into a vein through a catheter, which is surgically implanted. This may be partial, to supplement food and nutrient intake, or total (TPN, total parenteral nutrition), providing the sole source of energy and nutrient intake for the patient.

The origin and development of a disease or disorder.

The study of the fundamental nature, causes, and development of abnormal conditions and the structural and functional changes that result.

Changes or alterations in function that accompany a particular syndrome or disease, generally as distinguished from structural defects.

Having to do with the pelvis (the lower part of the abdomen located between the hip bones).

Peptic ulcer
A sore in the lining of the esophagus, stomach, or duodenum, usually caused by most commonly by the bacterium Helicobacter pylori (H. pylori) or use of NSAID medications. An ulcer in the stomach is a gastric ulcer; an ulcer in the duodenum is a duodenal ulcer.

The area of the body between the anus and the vulva in females, and between the anus and the scrotum in males.

The study of the functions or vital processes of living things.

Pilot study
The initial study examining a new method or treatment.

A benign growth involving the lining of the GI tract (noncancerous tumors or neoplasms). They can occur in several locations in the gastrointestinal tract but are most common in the colon. They vary in size from less than a quarter of an inch to several inches in diameter. They look like small bumps growing form the lining of the bowel and protruding into the lumen (bowel cavity). They sometimes grow on a "stalk" and look like mushrooms. Many patients have several polyps scattered in different parts of the colon.

After meals.

The proportion of people in the entire population who are found to be with a disease or disorder at a certain point in time (sometimes called a "cross section"), without regard to when they first got the disease.

Primary care
First contact medical care to patients.

Primary care physician
A doctor who manages a person's health care over time. A primary care doctor is able to give a wide range of care, including prevention and treatment, and can refer a patient to a specialist.

Primary lactase deficiency
When a person is born with the inability to digest lactose, a sugar found in milk and milk products. Lactose can't be digested because there is not enough of an enzyme, called lactase, in the body. Consuming milk and dairy products causes diarrhea, bloating, gas, and discomfort. This deficiency can also develop over time, as the amount of lactase in the body decreases with age.

A collection of current research reports, usually presented as brief abstracts, from a scientific meeting.

Progressive muscle relaxation
Voluntary relaxation through systematic tensing and relaxing of different muscle groups.

Drugs that enhance propulsion of contents through the gut.

Prospective study
A study that utilizes carefully defined protocols to determine an outcome that is unknown beforehand.

A protein that digests other proteins.

A large complex molecule made up of one or more chains of amino acids. Proteins perform a wide variety of activities in the cell.

An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered.

Proton pump inhibitor (PPI)
The strongest class of drugs for inhibiting acid secretion in the stomach.






Quality of life
Perception of ability to meet daily needs, physical activities, well-being.






Radiation proctitis
Bleeding, mucous and bloody discharge, spasm of the rectal wall, urgency, and incontinence due radiation-induced damage to the rectum. Late symptoms result from scarring of the rectal and anal muscles with loss of some of the small blood vessels. The rectum becomes stiff and noncompliant (nonstretchable) and abnormal blood vessels may develop.

Random allocation
A method where all participants in a study have the same chance of being assigned to a study group, rather than allocation being assigned by the investigators, clinicians, or participants.

Randomized controlled trial
A study in which people are allocated at random to receive one of several clinical interventions. One intervention is regarded as a standard of comparison or control.

A structure in each cell that selectively receives and binds a specific substance, such as a neurotransmitter.

The lower end of the large intestine, leading to the anus.

Resistant to treatment.

Resection, intestinal
The surgical removal of a diseased portion of the intestines.

Retrospective study
A study in which known outcomes are examined in hindsight using existing records. A retrospective study is usually less reliable than a prospective study.

A process in which chemical neurotransmitters, after transmitting their message, are taken up again by nerve endings, broken down, and inactivated.






Feeling of fullness.

Scientific knowledge
The current set of peer-evaluated consensus models about how natural phenomena work, which often differ between groups of researchers at the research frontier.

Scientific progress
The cumulative growth of a system of knowledge over time, in which useful features are retained and nonuseful features are abandoned, based on the rejection or confirmation of testable knowledge.

An imaging method in which a mild dose of a radioactive substance is swallowed to show how material moves through the GI tract.

Serotonin (5-hydroxytryptamine, or 5-HT)
A chemical neurotransmitter (a chemical that acts on the nervous system to help transmit messages along the nervous system). It is found in the intestinal wall and the central nervous system. It is now widely understood that 95% of the serotonin in the body resides in the gut.

Sigmoid colon
The S-shaped section of the colon that connects to the rectum.

Examination of the inside of the sigmoid colon and rectum using an endoscope -- a thin, lighted tube (sigmoidoscope). Samples of tissue or cells may be collected for examination under a microscope. Also called proctosigmoidoscopy. Skin test
A test for an immune response to a compound by placing it on or under the skin.

Small intestine
The part of the digestive tract that is located between the stomach and the large intestine.

Psychological needs expressed as physical symptoms.

Ring of muscle that opens and closes and acts as a valve in various "check points" of the GI tract.

Spinal cord
A column of nerve tissue that runs from the base of the skull down the back. It is surrounded by three protective membranes, and is enclosed within the vertebrae (back bones). The spinal cord and the brain make up the central nervous system, and spinal cord nerves carry most messages between the brain and the rest of the body.

Squamous cell
A flat cell that looks like a fish scale under a microscope. Squamous cells cover internal and external surfaces of the body.

Abnormal narrowing of a tubular part of the body.

A set of symptoms or conditions that occur together and suggest the presence of a certain disease or an increased chance of developing the disease.

Affecting the entire body.






Tertiary care
Medical care in a highly specialized center.

Translational science
Conversion of basic science discoveries into the practical applications that benefit people.






Ulcerative colitis
A form of inflammatory bowel disease that causes ulcers and inflammation in the inner lining of the colon and rectum.

An imaging method in which high-frequency sound waves are used to outline a part of the body.

Upper endoscopy
Examination of the inside of the esophagus, stomach, and duodenum using an endoscope.

Upper GI series
X-rays of the esophagus, stomach, and duodenum.






The extent to which a measure accurately reflects the concept that it is intended to measure.

Valsalva maneuver
Voluntary increasing pressure in the abdominal cavity with the diaphragm and abdominal muscles to bear down on the rectum to facilitate defecation.

Tiny finger-like projections on the surface of the small intestine that help absorb nutrients.

Visceral hypersensitivity
Enhanced perception, or over-responsiveness within the gut -- even to normal events.
























The preceding information is intended only to provide general information and not as a definitive basis for diagnosis or treatment in any particular case. It is very important that you consult your doctor about your specific condition.