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February 10, 2012

The Digestive System Glossary of Terms

The following are health and medical definitions of terms that appear in the The Digestive System article.

Absorb: 1. To take something in, as through the skin or the intestine.
2. To react with radiation and reduce it in intensity, as with a dose of radiation or transmitted light.
See also: Absorbed dose; Absorption; Malabsorption; Reabsorption.

Absorption: Uptake. In the biomedical sciences, absorption has diverse specific meanings.
See the entire definition of Absorption

Anus: The opening of the rectum to the outside of the body.
See the entire definition of Anus

Appendix: A small outpouching from the beginning of the large intestine (the ascending colon). Formally called the vermiform appendix because it was thought to be wormlike.
See the entire definition of Appendix

Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).
See the entire definition of Bacteria

Bile: Bile is a yellow-green fluid that is made by the liver, stored in the gallbladder and passes through the common bile duct into the duodenum where it helps digest fat. The principal components of bile are cholesterol, bile salts, and the pigment bilirubin.
See the entire definition of Bile

Bowel: Another name for the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively.
See the entire definition of Bowel

Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."

Carbohydrates: Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources (calories) by the body. Carbohydrates can also be defined chemically as neutral compounds of carbon, hydrogen and oxygen.
See the entire definition of Carbohydrates

Colon: The part of the large intestine that runs from the cecum to the rectum as a long hollow tube that serves to remove water from digested food and let the remaining material, solid waste called stool, move through it to the rectum and leave the body through the anus. .
See the entire definition of Colon

Digestive system: The organs that are responsible for getting food into and out of the body and for making use of it. These organs include the salivary glands, the mouth, esophagus, stomach, small intestine, liver, gallbladder, pancreas, colon, rectum, and anus.
See the entire definition of Digestive system

Duodenum: The first part of the small intestine. The duodenum extends from the pylorus at the bottom of the stomach to the jejunum, the second part of the small intestine. The duodenum is a common site for the formation of peptic ulcers. We often live with words without thinking where they come from or what they originally meant. That is the case for me with the duodenum. For decades, this writer knew the duodenum as a short but troubled sector of the small intestine. Only today did I learn that the duodenum began as the dodeka-daktulon, twelve fingers to the Greeks, who astutely observed that the duodenum is about 12 finger-breadths long. In German, the popular term for duodenum is Zwolffingerdarm, the 12-finger intestine.

Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction.
See the entire definition of Enzymes

Esophageal: Pertaining to the esophagus.

Esophagus: The tube that connects the pharynx (throat) with the stomach. The esophagus lies between the trachea (windpipe) and the spine. It passes down the neck, pierces the diaphragm just to the left of the midline, and joins the cardiac (upper) end of the stomach. In an adult, the esophagus is about 25 centimeters (10 inches) long. When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Glands in the lining of the esophagus produce mucus, which keeps the passageway moist and facilitates swallowing. Also known as the gullet or swallowing tube. From the Greek oisophagos, from oisein meaning to bear or carry + phagein, to eat.

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Fats: Plural of the word "fat". See the definition of fat.

Gallbladder: A pear-shaped organ just below the liver that stores the bile secreted by the liver. During a fatty meal, the gallbladder contracts, delivering the bile through the bile ducts into the intestines to help with digestion. Abnormal composition of bile leads to formation of gallstones, a process termed cholelithiasis. The gallstones cause cholecystitis, inflammation of the gallbladder.

GERD: Stands for Gastroesophageal Reflux Disease, a disorder in which there is recurrent return of stomach contents back up into the esophagus, frequently causing heartburn, a symptom of irritation of the esophagus by stomach acid. This can lead to scarring and stricture of the esophagus, which can require stretching (dilating).
See the entire definition of GERD

GI tract: Short for gastrointestinal tract. See: Gastrointestinal tract.

Heartburn: An uncomfortable feeling of burning and warmth occurring in waves rising up behind the breastbone (sternum) toward the neck. It is usually due to gastroesophageal reflux disease (GERD), the rise of stomach acid back up into the esophagus. Heartburn has nothing whatsoever to do with the heart. It is a popular nonmedical term. It is medically called pyrosis.

Ileum: The lowest part of the small intestine, located beyond the duodenum and jejunum, just before the large intestine (the colon). Pronounced "il-eum" in the US and "eye-leum" in the UK.
See the entire definition of Ileum

Intestine: The long, tubelike organ in the abdomen that completes the process of digestion. It consists of the small and large intestines.

Jejunum: Part of the small intestine. It is half-way down the small intestine between its duodenum and ileum sections.
See the entire definition of Jejunum

Large bowel: Another name for the large intestine.
See the entire definition of Large bowel

Large intestine: Comes after the small intestine. Large because it is wider than the small intestine.

Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.


See the entire definition of Liver

Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Muscular: Having to do with the muscles. Also, endowed with above average muscle development. Muscular system refers to all of the muscles of the body collectively.

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Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye, ear, heart, lungs, and liver.

Palate: The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).

Pancreas: A fish-shaped spongy grayish-pink organ about 6 inches (15 cm) long that stretches across the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen and is connected to the duodenum (the first section of the small intestine). The narrow end of the pancreas, called the tail, extends to the left side of the body.


See the entire definition of Pancreas

Pelvic: Having to do with the pelvis, the lower part of the abdomen, located between the hip bones.

Pelvis: The lower part of the abdomen located between the hip bones.

Peristalsis: The rippling motion of muscles in the digestive tract. In the stomach, this motion mixes food with gastric juices, turning it into a thin liquid.

Pharynx: The hollow tube about 5 inches long that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach).

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
See the entire definition of Protein

Rectum: The last 6 to 8 inches of the large intestine. The rectum stores solid waste until it leaves the body through the anus. The word rectum comes from the Latin rectus meaning straight (which the human rectum is not).

Reflex: A reaction that is involuntary. The corneal reflex is the blink that occurs with irritation of the eye. The nasal reflex is a sneeze.

Reflux: The term used when liquid backs up into the esophagus from the stomach.

Regurgitation: A backward flowing. For example, of food. Or the sloshing of blood back into the heart (or between chambers of the heart) when a heart valve is incompetent and does not close effectively.

Saliva: a watery secretion in the mouth produced by the salivary glands that aids in the digestion of food. Saliva also serves to moisten and cleanse the mouth, including the tongue and teeth, and contains substances that can play a role in the prevention of infection. Saliva aids digestion by moistening food and contains enzymes that begin the digestion process. Also known as spit.

Sensation: In medicine and physiology, sensation refers to the registration of an incoming (afferent) nerve impulse in that part of the brain called the sensorium, which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.)
See the entire definition of Sensation

Sigmoid: In human anatomy, the lower colon (the lower portion of the large bowel). "Sigmoid" is short for "sigmoid colon."
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Small intestine: The part of the digestive tract that extends from the stomach to the large intestine.

Soft palate: The muscular part of the roof of the mouth. The soft palate is directly behind the hard palate. It lacks bone and so is soft.

Stomach: 1. The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.
See the entire definition of Stomach

Stool: The solid matter discharged in a bowel movement.

Substance: 1. Material with particular features, as a pressor substance.
2. The material that makes up an organ or structure. Also known in medicine as the substantia.
3. A psychoactive drug as, for example, in substance abuse.

Taste: Taste belongs to our chemical sensing system, or the chemosenses. The complicated process of tasting begins when molecules released by the substances stimulate special cells in the mouth or throat. These special sensory cells transmit messages through nerves to the brain where specific tastes are identified.
See the entire definition of Taste

Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.

Tongue: The tongue is a strong muscle anchored to the floor of the mouth. It is covered by the lingual membrane which has special areas to detect tastes.
See the entire definition of Tongue

Trachea: A tube-like portion of the breathing or "respiratory" tract that connects the "voice box" (larynx) with the bronchial parts of the lungs.


See the entire definition of Trachea

Transverse: In anatomy, a horizontal plane passing through the standing body so that the transverse plane is parallel to the floor.
See the entire definition of Transverse

Vitamins: The word "vitamin" was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance "vitamine" because he believed it was necessary to life and it was a chemical amine. The "e" at the end was later removed when it was recognized that vitamins need not be amines.
See the entire definition of Vitamins

Voluntary: Done in accordance with the conscious will of the individual. The opposite of involuntary.
See the entire definition of Voluntary

Windpipe: The trachea, a tube-like portion of the respiratory (breathing) tract that connects the larynx (the voicebox) with the bronchial parts of the lungs.


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    • Abdominal Pain
      • Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
    • Rectal Bleeding
      • Rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Rectal bleeding may be moderate to severe and most bleeding comes from the colon, rectum, or anus. Common causes include anal fissures, hemorrhoids, diverticulitis, and more.
    • Gastroenteritis (Stomach Flu)
      • Gastroenteritis (viral gastroenteritis, stomach flu) is an infection caused by a variety of viruses that results in vomiting and/or diarrhea. Even though it is often called the "stomach flu," it is not caused by the influenza viruses. Viruses that can cause gastroenteritis (stomach flu) include: rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Noroviruses. Gastroenteritis is not caused by bacteria. The main symptoms of gastroenteritis include vomiting and watery diarrhea, however, headache, fever, and abdominal cramps (stomach ache) may also be present.
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      • Hemorrhoid is an enlarged vein in the walls of the anus and sometimes around the rectum, usually caused by untreated constipation, but occasionally associated with chronic diarrhea. If untreated, hemorrhoids can worsen, protruding from the anus. Also known as piles.
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      • Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
    • Appendicitis
      • Appendicitis is an inflammation of the appendix. Appendicitis often causes fever, loss of appetite, and right lower quadrant abdominal pain. Delay in surgery can result in appendix rupture with potentially serious complications.
    • Gallstones
      • Gallstones are stones that form when substances in the bile harden. Gallstones (formed in the gallbladder) can be as small as a grain of sand or as large as a golf ball. There can be just one large stone, hundreds of tiny stones, or any combination. The majority of gallstones do not cause symptoms.
    • Intestinal Gas
      • Gas or "intestinal gas" means different things to different people. Everyone has gas and eliminates it by belching or farting (passing it through the rectum).
    • Gastroesophageal Reflux Disease (GERD)
      • GERD (gastroesophageal reflux disease) is a condition in which the acidified liquid contents of the stomach backs up into the esophagus. The symptoms of uncomplicated GERD are heartburn, regurgitation, and nausea. Effective treatment is available for most patients with GERD.
    • Constipation
      • Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week. Constipation usually is caused by the slow movement of stool through the colon. There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
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      • Diverticulitis is a condition in which diverticuli in the colon rupture. The rupture results in infection in the tissues that surround the colon. Diverticulitis symptoms include: abdominal pain, abdominal cramps, diarrhea, constipation, and bloating. Treatment methods include prescription medications, and in some cases, diverticulitis surgery.
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      • Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect other parts of the digestive system as well. Abdominal pain, diarrhea, vomiting, fever, and weight loss are common symptoms.
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      • Liver cancer is the fifth most common cancer in the world and the majority of patients with liver cancer will die within one year as a result. Patients with associated cirrhosis caused by chronic hepatitis B or C infections, alcohol, and hemochromatosis are at the greatest risk of developing liver cancer. Many patients with liver cancer do not develop symptoms until the advanced stages of the tumor which usually makes prognosis poor. The combination of an imaging study (ultrasound, CT, or MRI scans) and an elevated blood level of alpha-fetoprotein will most effectively diagnose liver cancer, while a liver biopsy can make a definitive diagnosis. Medical treatments, including chemotherapy, chemoembolization, ablation, and proton beam therapy, are not very effective. Surgical removal of the tumor or a liver transplant may be most effective in certain cases.
    • Cirrhosis (Liver)
      • Cirrhosis of the liver refers to a disease in which normal liver cells are replaced by scar tissue caused by alcohol and viral hepatitis B and C. This disease leads to abnormalities in the liver's ability to handle toxins and blood flow, causing internal bleeding, kidney failure, mental confusion, coma, body fluid accumulation, and frequent infections. Symptoms include yellowing of the skin, itching, and fatigue.
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      • A hiatal hernia is an anatomical abnormality in which part of the stomach protrudes through the diaphragm and up into the chest. Causes of hiatal hernia are a larger than normal esophageal hiatus. There are two types of hiatal hernias, sliding, or para-esophageal. When symptoms of hiatal hernia appear, they are similar to GERD symptoms. Hiatal hernia treatment is generally surgery.
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      • Pancreatic cancer is a malignant tumor of the pancreas. Pancreatic cancer has been called a "silent" disease because early pancreatic cancer usually does not cause symptoms.
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      • Colon cancer is a malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from colonic polyps. Removal of these precancerous polyps can prevent colon cancer.
    • Stomach Cancer
      • Though the cause of stomach cancer is unknown, risk factors for stomach cancer include diet, H. pylori infection, smoking age, gastritis, stomach surgery, family history, and pernicious anemia. Symptoms include stomach discomfort, feeling full after a small meal, nausea and vomiting, and weight loss. Treatment depends upon staging and may involve surgery, radiation therapy, or chemotherapy.
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      • An anal fissure is a small tear or cut in the skin lining of the anus. Pain and/or rectal bleeding during bowel movements are common symptoms of anal fissures. Treatment involves increasing liquid intake, using stool softeners and avoiding foods that may not be well-digested.
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      • In lactose intolerance, the digestive system cannot digest lactose (the main sugar in milk). Symptoms of lactose intolerance include diarrhea, flatulence, abdominal pain, abdominal bloating, abdominal distention, and nausea. There are several tests to diagnose lactose intolerance. Treatment is generally made with dietary changes, supplements, and adaptation to small amounts of milk.
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      • IBS (irritable bowel syndrome) is a common gastrointestinal disorder involving abnormal gut contractions (motility) characterized by abdominal pain, bloating, mucous in stools, and irregular bowel habits with alternating diarrhea and constipation, symptoms that tend to be chronic and to wax and wane over the years. Treatment options include medication and lifestyle changes such as diet, exercise, and stress management to control symptoms. Also called spastic colitis, mucus colitis, nervous colon syndrome.
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      • Stool color is generally brown. When stool color changes, often, an individual becomes concerned. The presence of the bilirubin in bile is generally responsible for stool color. Bilirubin concentration can vary bile color from light yellow to almost black in color. Changes in bilirubin can cause stool to turn green, gray, or clay-like in color. Intestinal bleeding may turn stool black, tarry, red, maroon, or smelly stool. Medication and food may also affect stool color.
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The Digestive System

How is the procedure performed?

Three or more small (5-10 mm) incisions are made in the abdomen to allow access ports to be inserted. The laparoscope and surgical instruments are inserted through these ports. The surgeon then uses the laparoscope, which transmits a picture of the abdominal organs on a video monitor, allowing the operation to be performed.

Laparoscopic intestinal surgery can be used to perform the following operations:

  • Proctosigmoidectomy. Surgical removal of a diseased section of the rectum and sigmoid colon. Used to treat cancers and noncancerous growths or polyps, and complications of diverticulitis.
  • Right colectomy or Ileocolectomy. During a right colectomy, the right side of the colon is removed. During an ileocolectomy, the last segment of the small intestine - which is attached to the right side of the colon, called the ileum, is also removed. Used to remove cancers, noncancerous growths or po...

Read the Laparoscopy article »







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