gait - pattern of locomotion.    

ganglion - a cluster of nerve cells.    

ganglion cysts - non-cancerous, fluid-filled cysts are common masses or lumps in the hand and usually found on the back of the wrist.

Gardner's syndrome - condition in which many polyps form throughout the digestive tract.

gas - air that comes from the normal breakdown of food and is passed out of the body through the rectum (flatus) or the mouth (belch).

gastric - related to the stomach.

gastric juices - liquids produced in the stomach to help break down food and kill bacteria.

gastrocolic reflex - increase of muscle movement in the gastrointestinal tract when food enters an empty stomach; may cause the urge to have a bowel movement right after eating.

gastroenteritis - infection or irritation of the stomach and intestines, which may be caused by bacteria or parasites from spoiled food or unclean water, or eating food that irritates the stomach lining and emotional upsets such as anger, fear, or stress.

gastroenterologist - physician who specializes in digestive diseases.

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

gastrointestinal (GI) tract (Also called the alimentary canal or digestive tract.) - a large, muscular tube that extends from the mouth to the anus, where the movement of muscles and release of hormones and enzymes digest food.  

gastrostomy - an artificial opening from the stomach to a hole (stoma) in the abdomen where a feeding tube is inserted. (See also enteral nutrition.)

general anesthetic - an anesthetic which causes the patient to become unconscious during surgery.

genes - basic, functional units of heredity, each occupying a specific place on a chromosome.

genital herpes - a sexually transmitted disease caused by the herpes simplex virus.  

glucose - a simple sugar, which is the body's main source of energy.   

gluten sensitive enteropathy (Also called celiac sprue or celiac disease.) - a sensitivity to gluten - a wheat protein. Individuals with this disease must avoid gluten-containing grains, which include all forms of wheat, oats, barley, and rye.

gluteus maximus - the large, superficial buttock muscle.

glycogen - converted glucose for storage. Glycogen plays a role in controlling blood sugar levels.

gonads - ovaries and testes.

grades of movement - standardized means of documenting techniques of mobilization, relating it to the true feel of joint movement.

grading - a process for classifying cancer cells to determine the growth rate of the tumor. The cancer cells are measured by how closely they look like normal cells.   

granuloma - mass of red, irritated tissue in the gastrointestinal tract found in Crohn's disease. 

gray matter - the darker-colored tissues of the central nervous system; in the brain, the gray matter includes the cerebral cortex, the thalamus, the basal ganglia, and the outer layers of the cerebellum.

gustation - act or sensation of tasting.