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 The Digestive System Main Article |  Glossary |  The Digestive System Index 

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

Accessory: Additional, extra, supplementary, subsidiary to the main thing. An accessory digestive organ is an organ that helps with digestion but is not part of the digestive tract. The accessory nerve is so-called because it receives an additional (accessory) root from the upper part of the spinal cord. An accessory placenta is an extra placenta separate from the main placenta.

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

Blood: The familiar red fluid in the body that contains white and red blood cells, platelets, proteins, and other elements. The blood is transported throughout the body by the circulatory system. Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.

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."
See the entire definition of Brain

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

Condition: The term "condition" has a number of biomedical meanings including the following:

  1. An unhealthy state, such as in "this is a progressive condition."
  2. A state of fitness, such as "getting into condition."
  3. Something that is essential to the occurrence of something else; essentially a "precondition."
  4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

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 Zwölffingerdarm, the 12-finger intestine.

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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.

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.

Gastroenterology: The medical specialty devoted to the study, diagnosis and treatment of disorders of the digestive system . These disorders may affect the esophagus (swallowing tube), stomach , small intestine , large intestine ( colon ), rectum , liver , gallbladder , or pancreas .
See the entire definition of Gastroenterology

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 back to top

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.

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).
See the entire definition of 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.
See the entire definition of Reflex

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.
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Rest: 1. Repose. Relaxation.
2. A fragment of embryonic tissue that has been retained after the period of embryonic development. Also called an embryonic rest.

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."
See the entire definition of Sigmoid

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 .
See the entire definition of Throat

Toilet: 1. In medicine, cleansing of a wound and the skin around it. 2. In obstetrics, cleansing of a woman just after childbirth. 3. In dentistry, the cleaning out of a cavity before a restoration. 4. A device for the disposal of urine and feces. Or the room containing such a device.
See the entire definition of Toilet

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.
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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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 The Digestive System Main Article |  Glossary |  The Digestive System Index 




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The Digestive System

What Is Pernicious Anemia?

Pernicious anemia (per-NISH-us uh-NEE-me-uh) is a condition in which the body does not make enough red blood cells due to a lack of vitamin B12 in the body. It usually occurs in people whose bodies have lost the ability to absorb vitamin B12 from food.

Anemia

Pernicious anemia is one of many different types of anemia. Having anemia means you do not have enough healthy red blood cells. When a person has anemia, the blood cannot carry enough oxygen to the cells of the body. The most common symptom of anemia is feeling tired.

Pernicious Anemia

In pernicious anemia, the blood cells do not divide normally and are too large. They have trouble getting out of the bone marrow. The problem is due to a lack of vitamin B12 in the body. Vitamin B12 is one of the B vitamins; B vitamins are found in animal foods such as meat, fish, eggs, milk, and other dairy products. Vitamin B12 is necess...

Read the Pernicious Anemia article »










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