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Understanding Nutrition Chapter 3- 12th edition- Whitney|Rolfes This material was found at ( or the text book companion site.

a word ending denoting an enzyme. The word beginning often identifies the compounds the enzyme works on. Examples include: carbohydrases, lipases, and proteases.


the uptake of nutrients by the cells of the small intestine for transport into either the blood or the lymph.


medications used to prevent or relieve indigestion by suppressing production of acid in the stomach; also called H2 blockers. Common brands include Pepcid AC, Tagamet HB, Zantac 75, and Axid AR.

acid controllers

medications used to relieve indigestion by neutralizing acid in the stomach. Common brands include Alka-Seltzer, Maalox, Rolaids, and Tums.


the terminal outlet of the GI tract.

anus (AY-nus)

the large, primary artery that conducts blood from the heart to the body's smaller arteries.

aorta (ay-OR-tuh)

a narrow blind sac extending from the beginning of the colon that stores lymph cells.


vessels that carry blood from the heart to the tissues.


the expulsion of gas from the stomach through the mouth.


an alkaline compound with the formula HCO3 that is secreted from the pancreas as part of the pancreatic juice. (Bicarbonate is also produced in all cell fluids from the dissociation of carbonic acid to help maintain the body's acid-base balance.)


an emulsifier that prepares fats and oils for digestion; an exocrine secretion made by the liver, stored in the gallbladder, and released into the small intestine when needed.


a portion; with respect to food, the amount swallowed at one time.

bolus (BOH-lus)

small vessels that branch from an artery. Capillaries connect arteries to veins. Exchange of oxygen, nutrients, and waste materials takes place across capillary walls.

capillaries (CAP-ill-aries)

an enzyme that hydrolyzes carbohydrates.

carbohydrase (KAR-boe-HIGH-drase)

a compound that facilitates chemical reactions without itself being changed in the process.

catalyst (CAT-uh-list)

a hormone produced by cells of the intestinal wall. Target organ: the gallbladder. Response: release of bile and slowing of GI motility.

cholecystokinin (COAL-ee-SIS-toe-KINE-in)

the semiliquid mass of partly digested food expelled by the stomach into the duodenum.

chyme (KIME)

inflammation of the colon.

colitis (ko-LYE-tis)

the popular, but potentially harmful practice of "washing" the large intestine with a powerful enema machine.

colonic irrigation

the condition of having infrequent or difficult bowel movements.


tubular glands that lie between the intestinal villi and secrete intestinal juices into the small intestine.

crypts (KRIPTS)

to move the bowels and eliminate waste.

defecate (DEF-uh-cate)

the frequent passage of watery bowel movements.


the process by which food is broken down into absorbable units.


proteins found in digestive juices that act on food substances, causing them to break down into simpler compounds.

digestive enzymes

all the organs and glands associated with the ingestion and digestion of food.

digestive enzymes

sacs or pouches that develop in the weakened areas of the intestinal wall (like bulges in an inner tube where the tire wall is weak).

diverticula (dye-ver-TIC-you-la)

infected or inflamed diverticula.

diverticulitis (DYE-ver-tic-you-LYE-tis)

the condition of having diverticula. About one in every six people in Western countries develops diverticulosis in middle or later life.

diverticulosis (DYE-ver-tic-you-LOH-sis)

the top portion of the small intestine (about "12 fingers' breadth" long in ancient terminology).

duodenum (doo-oh-DEEN-um, doo-ODD-num)

a substance with both water-soluble and fat-soluble portions that promotes the mixing of oils and fats in a watery solution.

emulsifier (ee-MUL-sih-fire)

solutions inserted into the rectum and colon to stimulate a bowel movement and empty the lower large intestine.


cartilage in the throat that guards the entrance to the trachea and prevents fluid or food from entering it when a person swallows.

epiglottis (epp-ih-GLOTT-iss)

a sphincter muscle at the upper or lower end of the esophagus. The lower esophageal sphincter is also called the cardiac sphincter.

esophageal sphincter (ee-SOF-ah-GEE-al)

the food pipe; the conduit from the mouth to the stomach.

esophagus (ee-SOFF-ah-gus)

the organ that stores and concentrates bile. When it receives the signal that fat is present in the duodenum, the gallbladder contracts and squirts bile through the bile duct into the duodenum.


exocrine glands in the stomach wall that secrete gastric juice into the stomach.

gastric glands

the digestive secretion of the gastric glands of the stomach.

gastric juice

a hormone secreted by cells in the stomach wall. Target organ: the glands of the stomach. Response: secretion of gastric acid.


the backflow of stomach acid into the esophagus, causing damage to the cells of the esophagus and the sensation of heartburn. Gastroesophageal reflux disease (GERD) is characterized by symptoms of reflux occurring two or more times a week.

gastroesophageal reflux

the digestive tract. The principal organs are the stomach and intestines.

gastrointestinal (GI) tract

cells or groups of cells that secrete materials for special uses in the body. Glands may be exocrine (EKS-oh-crin) glands, secreting their materials "out" (into the digestive tract or onto the surface of the skin), or endocrine (EN-doe-crin) glands, secreting their materials "in" (into the blood).


cells of the GI tract (and lungs) that secrete mucus.

goblet cells

a burning sensation in the chest area caused by backflow of stomach acid into the esophagus.


a technique for dislodging an object from the trachea of a choking person; named for the physician who developed it.

Heimlich maneuver (abdominal thrust maneuver) (HIME-lick)

painful swelling of the veins surrounding the rectum.

hemorrhoids (HEM-oh-royds)

the vein that collects blood from the GI tract and conducts it to capillaries in the liver.

hepatic portal vein

the vein that collects blood from the liver capillaries and returns it to the heart.

hepatic vein

repeated cough-like sounds and jerks that are produced when an involuntary spasm of the diaphragm muscle sucks air down the windpipe; also spelled hiccoughs.

hiccups (HICK-ups)

the maintenance of constant internal conditions (such as blood chemistry, temperature, and blood pressure) by the body's control systems. A homeostatic system is constantly reacting to external forces to maintain limits set by the body's needs.

homeostasis (HOME-ee-oh-STAY-sis)

chemical messengers. Hormones are secreted by a variety of glands in response to altered conditions in the body. Each hormone travels to one or more specific target tissues or organs, where it elicits a specific response to maintain homeostasis.


an acid composed of hydrogen and chloride atoms (HCl) that is normally produced by the gastric glands.

hydrochloric acid

a chemical reaction in which a major reactant is split into two products, with the addition of a hydrogen atom (H) to one and a hydroxyl group (OH) to the other (from water, H2O). (The noun is hydrolysis; the verb is hydrolyze.)

hydrolysis (high-DROL-ih-sis)

the sphincter separating the small and large intestines.

ileocecal valve (ill-ee-oh-SEEK-ul)

the last segment of the small intestine.

ileum (ILL-ee-um)

incomplete or uncomfortable digestion, usually accompanied by pain, nausea, vomiting, heartburn, intestinal gas, or belching.


an intestinal disorder of unknown cause. Symptoms include abdominal discomfort and cramping, diarrhea, constipation, or alternating diarrhea and constipation.

irritable bowel syndrome

the first two-fifths of the small intestine beyond the duodenum.

jejunum (je-JOON-um)

the lower portion of intestine that completes the digestive process. Its segments are the ascending colon, the transverse colon, the descending colon, and the sigmoid colon.

large intestine or colon (COAL-un)

the entryway to the trachea that contains the vocal cords; also called the voice box.

larynx (LAIR-inks)

substances that loosen the bowels and thereby prevent or treat constipation.


an enzyme that hydrolyzes lipids (fats).

lipase (LYE-pase)

the organ that manufactures bile.


the space within a vessel, such as the intestine.

lumen (LOO-men)

a clear yellowish fluid that is similar to blood except that it contains no red blood cells or platelets. Lymph from the GI tract transports fat and fat-soluble vitamins to the bloodstream via lymphatic vessels.

lymph (LIMF)

a loosely organized system of vessels and ducts that convey fluids toward the heart. The GI part of the lymphatic system carries the products of fat digestion into the bloodstream.

lymphatic system (lim-FAT-ic)

tiny, hairlike projections on each cell of every villus that can trap nutrient particles and transport them into the cells; singular microvillus.

microvilli (MY-cro-VILL-ee, MY-cro-VILL-eye)

a purified liquid derived from petroleum and used to treat constipation.

mineral oil

the oral cavity containing the tongue and teeth.


a slippery substance secreted by cells of the GI lining (and other body linings) that protects the cells from exposure to digestive juices (and other destructive agents). The lining of the GI tract with its coat of mucus is a mucous membrane. (The noun is mucus; the adjective is mucous.)

mucus (MYOO-kus)

a gland that secretes digestive enzymes and juices into the duodenum. (The pancreas also secretes hormones into the blood that help to maintain glucose homeostasis.)


the exocrine secretion of the pancreas, containing enzymes for the digestion of carbohydrate, fat, and protein as well as bicarbonate, a neutralizing agent. The juice flows from the pancreas into the small intestine through the pancreatic duct. (The pancreas also has an endocrine function, the secretion of insulin and other hormones.)

pancreatic juice (pank-ree-AT-ic)

a lesion in the mucous membrane of either the stomach (a gastric ulcer) or the duodenum (a duodenal ulcer).

peptic ulcer

wavelike muscular contractions of the GI tract that push its contents along.

peristalsis (per-ih-STALL-sis)

the unit of measure expressing a substance's acidity or alkalinity.


the passageway leading from the nose and mouth to the larynx and esophagus, respectively.

pharynx (FAIR-inks)

living microorganisms found in foods and dietary supplements that, when consumed in sufficient quantities, are beneficial to health.


an enzyme that hydrolyzes proteins.

protease (PRO-tee-ase)

the circular muscle that separates the stomach from the small intestine and regulates the flow of partially digested food into the small intestine; also called pylorus or pyloric valve.

pyloric sphincter (pie-LORE-ic)

the muscular terminal part of the intestine, extending from the sigmoid colon to the anus.


a backward flow.


the secretion of the salivary glands. Its principal enzyme begins carbohydrate digestion.


exocrine glands that secrete saliva into the mouth.

salivary glands

a hormone produced by cells in the duodenum wall. Target organ: the pancreas. Response: secretion of bicarbonate-rich pancreatic juice.

secretin (see-CREET-in)

a periodic squeezing or partitioning of the intestine at intervals along its length by its circular muscles.

segmentation (SEG-men-TAY-shun)

a 10-foot length of small-diameter intestine that is the major site of digestion of food and absorption of nutrients. Its segments are the duodenum, jejunum, and ileum.

small intestine

a circular muscle surrounding, and able to close, a body opening. Sphincters are found at specific points along the GI tract and regulate the flow of food particles.

sphincter (SFINK-ter)

a muscular, elastic, saclike portion of the digestive tract that grinds and churns swallowed food, mixing it with acid and enzymes to form chyme.


waste matter discharged from the colon; also called feces (FEE-seez).


the vein that provides passage from the lymphatic system to the vascular system.

subclavian vein (sub-KLAY-vee-an)

the main lymphatic vessel that collects lymph and drains into the left subclavian vein.

thoracic duct (thor-ASS-ic)

the airway from the larynx to the lungs; also called the windpipe.

trachea (TRAKE-ee-uh)

a lesion of the skin or mucous membranes characterized by inflammation and damaged tissues. See also peptic ulcer.


vessels that carry blood to the heart.

veins (VANES)

fingerlike projections from the folds of the small intestine; singular villus.

villi (VILL-ee, VILL-eye)

expulsion of the contents of the stomach up through the esophagus to the mouth.




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