Dictionary

Body systems

Anatomy and the conditions of each body system, from the heart and lungs to the skin.

gestational diabetesHigh blood sugar that first develops during pregnancy in a person who did not have diabetes before.

gestational hypertensionHigh blood pressure that starts after 20 weeks of pregnancy in a person whose blood pressure was normal before.

gingivaThe gums: the firm pink tissue that covers the jawbone and surrounds the base of the teeth.

gingivitisInflammation of the gums.

glandAn organ or group of cells that makes and releases a substance the body uses, such as a hormone, sweat or saliva.

Glasgow Coma ScaleA scoring tool that rates a person's level of consciousness by their eye opening, verbal response and movement, from 3 to 15.

glaucomaAn eye disease in which the optic nerve is damaged, usually with raised pressure inside the eye, leading to loss of vision.

glomerularRelating to the glomerulus, the tiny cluster of capillaries in each nephron of the kidney that filters the blood.

glomerular filtrationThe first step in making urine, when the kidneys' tiny filters let water and small substances pass out of the blood.

glomerular filtration rateHow much blood the kidneys filter each minute, used as the main measure of kidney function.

glomerulonephritisInflammation of the glomeruli, the tiny filtering units of the kidneys.

glomerulusA tiny ball of capillaries in the kidney that filters the blood as the first step in making urine.

gluconeogenesisThe making of new glucose by the body from substances that are not carbohydrates, such as protein and fat.

glucoseA simple sugar that is the body's main source of energy.

glutamateThe main chemical messenger in the brain that excites nerve cells, making them more likely to fire.

glycogenThe stored form of glucose, kept mainly in the liver and muscles.

glycolysisThe first stage of breaking down glucose inside a cell to release energy.

goiterAn enlarged thyroid gland, seen or felt as a swelling at the front of the neck.

gonadA sex gland: an ovary or a testis, which makes eggs or sperm and sex hormones.

gonorrheaA bacterial infection, spread mainly through sex, caused by Neisseria gonorrhoeae.

Goodell signSoftening of the cervix felt in early pregnancy.

goutA form of arthritis in which crystals of uric acid collect in and around a joint.

granulation tissueNew, moist, red tissue that fills a healing wound from the bottom up.

Graves diseaseAn autoimmune disease in which antibodies make the thyroid gland overactive.

gravidaA pregnant woman; in a pregnancy history, the number of times a person has been pregnant, including now.

gray matterNerve tissue made mostly of nerve cell bodies, found on the outer layer of the brain and in the center of the spinal cord.

groinThe area where the upper thigh meets the lower belly, on each side.

growth and developmentThe changes in body size (growth) and in skills and abilities (development) that happen across a person's life.

growth hormoneA hormone from the pituitary gland that drives growth in children and helps control body build and metabolism in adults.

Guillain-Barre syndromeA rare autoimmune disorder in which the immune system attacks the nerves outside the brain and spinal cord.

gynecologyThe branch of medicine that cares for the female reproductive organs and breasts.

gynecomastiaEnlarged breast gland tissue in a male.

hair follicleA small tube-shaped pocket in the skin from which a hair grows.

hallucinationHearing, seeing, feeling, smelling or tasting something that is not really there.

hard palateThe bony front part of the roof of the mouth.

Hashimoto thyroiditisAn autoimmune disease in which the immune system attacks the thyroid gland, slowly reducing its hormone output.

head and neck cancerCancer that starts in the mouth, throat, voice box, nose, sinuses or salivary glands.

heart diseaseA general term for any condition that affects the structure or function of the heart.

heart failureA long-term condition in which the heart cannot pump enough blood to meet the body's needs.

heart murmurA whooshing or swishing sound heard with a stethoscope, made by blood flowing unevenly through the heart.

heart rateHow many times the heart beats per minute.

heartburnA burning feeling behind the breastbone or in the upper belly, often rising toward the throat.

heavy metalA dense metal, such as lead, mercury or arsenic, that can poison the body even in small amounts.

HELLP syndromeA severe complication of pregnancy whose name stands for hemolysis, elevated liver enzymes and low platelets.

hematemesisVomiting blood, either bright red or dark and grainy like coffee grounds.

hematomaA collection of blood, often clotted, that has leaked out of the blood vessels into the tissue.

hematuriaBlood in the urine, either seen by eye or found only by a test.

hemiplegiaParalysis of one side of the body.

hemodynamicsThe study and measurement of blood flow and the pressures that move blood through the heart and vessels.

hemoglobinThe iron-containing protein in red blood cells that carries oxygen, and the blood test that measures it.