Glossary of Terms

• Absorb: 1. To take something in, as through the skin or the intestine.

• 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

• 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.

• 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.

• 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." 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.

• 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.