Medical Glossary Index:

G

Galactocele- a milk-filled tumor in a blocked breast milk duct

Galactorrhea- breast milk production by a woman who is not pregnant and has not just given birth

Galactose- a sugar that is formed from the breakdown of lactose

Galactosemia- a genetic disorder in which galactose cannot be converted into glucose

Gallbladder- a small, pear-shaped sac positioned under the liver, which concentrates and stores bile

Gallstone- a round, hard mass of cholesterol, bile, or calcium salts that is found in the gallbladder or a bile duct

Gallstone ileus- an abnormal condition in which a gallstone passes from the gallbladder into the intestines through an abnormal passage and blocks the intestine

Gamete intrafallopian transfer- a method of treating infertility in which eggs are taken from a woman's ovaries and fertilized with sperm and then the fertilized egg is injected into one of her fallopian tubes

Gamma globulin- a substance prepared from blood that carries antibodies to most common infections; also used in immunizations

Ganglion- a fluid-filled cyst attached to a tendon sheath or joint

Gangrene- death of a tissue because of a lack of blood supply

Gastrectomy- surgical removal of all or part of the stomach

Gastric acid- the digestive acid in the stomach

Gastric juice- digestive fluids produced by the lining of the stomach that break down proteins and destroy harmful organisms

Gastric lavage- washing out of the stomach with water, often to treat poisoning; commonly called "stomach pumping"

Gastric ulcer- a peptic ulcer

Gastrin- a hormone that stimulates the release of gastric acid in the stomach

Gastrinoma- a tumor that produces gastrin, making the stomach and duodenum more acidic

Gastritis- inflammation of the mucous membrane lining of the stomach; can have
a number of causes, including viruses, bacteria, and use of alcohol and other drugs

Gastroenteritis- inflammation of the stomach and intestines

Gastrointestinal series- a set of X-rays, taken at different intervals after a barium sulfate solution is swallowed, to examine the gastrointestinal tract

Gastrointestinal tract- the part of the digestive system that includes the mouth, esophagus, stomach, and intestines

Gastroscopy- examination of the esophagus, stomach, and the first part of the small intestine (duodenum) using an endoscope inserted through the mouth

Gastrostomy- the surgical creation of an opening in the abdominal wall into the stomach for drainage or a feeding tube

Gaucher’s disease- a genetic disorder in which lipids cannot be properly broken down and build up in certain cells; causes enlargement of the spleen and liver, bone damage, and anemia

Gavage- an artificial feeding technique in which liquids are passed into the stomach by way of a tube inserted through the nose

Gene- the basic unit of DNA, which is responsible for passing genetic information; each gene contains the instructions for the production of a certain protein

General anesthesia- a method of preventing pain in which the patient is induced to lose consciousness

Generic drug- a drug marketed under its chemical name, instead of a brand name

Gene therapy- an experimental procedure in which disease-causing genes are replaced by normal, healthy genes

Genetic analysis- examination of DNA in a laboratory to diagnose genetic disorders

Genetic counseling- information and advice given to persons considering pregnancy about the risk that a child will have an inheritable birth defect or genetic disorder

Genetic disorder- a disorder caused partly or completely by a defect in genes, which carry hereditary information

Genetic engineering- the alteration of genetic information to change an organism; mainly used to produce vaccines and drugs such as insulin

Genital herpes- an infection caused by the herpes simplex virus, which causes a painful rash of fluid-filled blisters on the genitals; transmitted through sexual contact

Genital tract- the organs that make up the reproductive system

Genital wart- a growth on the skin in or around the vagina, penis, or anus, transmitted by sexual contact; can cause cancer of the cervix

Genome- the complete set of an organism’s genes

Geographic tongue- a condition in which the tongue is patchy where surface cells break down

German measles- the common name for Rubella

Germ cell- a sperm or egg cell, or the immature form of either

Gestation- the period of time between fertilization of an egg by a sperm and birth of a baby

Giardiasis- infection with a single-celled parasite, causing abdominal cramps, diarrhea, and nausea

GIFT- see Gamete intrafallopian transfer

Gingivectomy- surgical removal of a diseased part of the gums

Gingivitis- inflammation of the gums, typically caused by a buildup of plaque due to poor hygiene

GI series- see Gastrointestinal series

Gland- a group of cells or an organ that produces substances (such as hormones and enzyme) that are used by the body

Glaucoma- a disease in which eye damage is caused by an increase in the pressure of the fluid within the eye

Glioblastoma multiforme- a fast-growing, cancerous brain tumor

Glioma- a brain tumor arising from cells that support nerve cells

Glomerulonephritis- inflammation of the filtering structures in the kidneys, hindering removal of waste products from the blood

Glomerulosclerosis- scarring of the filtering structures in the kidneys due to damage

Glossectomy- surgical removal of all or part of the tongue

Glucagon- a hormone produced by the pancreas that converts stored carbohydrates (glycogen) into glucose, the body’s energy source

Glucose- a sugar that is the main source of energy for the body

Glucose tolerance test- a test that evaluates the body's response to glucose
after a period of fasting; used to check for diabetes mellitus

Glycogen- the main form that glucose, the body’s energy source, takes when it is stored

Glycosuria- glucose in the urine

Goiter- enlargement of the thyroid gland, which produces a swelling on the neck

Gonadotropic hormones- hormones that stimulate activity in the ovaries and testicles

Gonorrhea- a common sexually transmitted disease, characterized by painful urination or a discharge from the penis or vagina

Gout- a disorder marked by high levels of uric acid in the blood; usually experienced as arthritis in one joint

Graft- healthy tissue that is used to replace diseased or defective tissue

Grand mal- a type of seizure occurring with epilepsy, producing loss of consciousness and involuntary jerking movements

Granuloma- a mass of tissue that forms at a site of inflammation, injury, or infection as a part of the healing process

Graves' disease- an autoimmune disease that causes goiter, overproduction of thyroid hormones, and sometimes bulging eyeballs

Guillain-Barré syndrome- a peripheral nervous system disease in which nerve inflammation causes weakness, loss of movement, and loss of sensation in the arms and legs

Guthrie test- a blood test performed on babies to test for phenylketonuria