Dictionary

Body systems

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

equilibriumA state of balance, either of the body's position or of substances and forces within it.

Erb palsyWeakness or paralysis of one arm from stretching of the upper nerves of the brachial plexus, the nerve bundle between the neck and shoulder, usually at birth.

erectile dysfunctionRepeated trouble getting or keeping an erection firm enough for sex.

erythemaRedness of the skin caused by more blood flowing in the small vessels near the surface.

erythropoietinA hormone made mainly by the kidneys that tells the bone marrow to make red blood cells.

escharThick, dry, dark dead tissue that covers part or all of a wound.

esophagusThe muscular tube that carries food and liquid from the throat to the stomach.

estrogenA female sex hormone, made mainly by the ovaries, and the group of drugs that act like it.

etiologyThe cause or origin of a disease, or the study of causes of disease.

eviscerationThe pushing out of internal organs, usually loops of bowel, through a surgical wound that has come open.

exacerbationA time when a long-term disease suddenly gets worse, or its symptoms flare up.

excoriationA raw, scraped area of skin where the top layer has been scratched or rubbed away.

excreteTo get rid of waste from the body, in urine, stool, sweat or breath.

excretionThe removal of wastes, or of a drug and its breakdown products, from the body.

exhalationBreathing out: moving air out of the lungs.

expirationBreathing out; letting air flow out of the lungs. Also the date after which a product should not be used.

extracellular fluidAll the body's water that is outside the cells, in the blood vessels and in the spaces between cells.

extremityAn arm or a leg.

eyelidEither of the two folds of skin and muscle that cover and protect the front of the eye.

facial nerveThe seventh cranial nerve, which moves the muscles of the face and carries taste from the front of the tongue.

FADH₂The reduced form of flavin adenine dinucleotide, a molecule that carries electrons inside cells during energy production.

failure to thrivePoor growth in a child, with weight gain well below what is expected for the child's age.

fallopian tubeOne of the two tubes that carry an egg from the ovary to the uterus, where fertilization usually happens.

fasciaA sheet or band of tough connective tissue that covers and separates muscles and organs.

fatty acidA building block of fats: a chain of carbon atoms that the body uses for energy and to build cells.

febrile seizureA seizure in a young child brought on by a fever, without an infection of the brain or another known cause.

fecalHaving to do with feces, the solid waste passed from the bowel; stool.

fecesSolid waste passed from the bowel through the anus, made of undigested food, water, bacteria and cells.

feedbackInformation about a result that is sent back to change what happens next, in the body or between people.

femoralRelating to the thigh or the femur, the thigh bone.

femoral arteryThe large artery that carries blood to the leg, running through the groin and down the thigh.

femurThe thigh bone, the long bone between the hip and the knee.

fertilityThe ability to become pregnant or to cause a pregnancy.

fertilizationThe joining of a sperm and an egg to form a single new cell, the start of a pregnancy.

fetalRelating to a fetus, the unborn baby from the ninth week of pregnancy until birth.

fetal heart rateThe number of times the unborn baby's heart beats per minute.

fetal heart rate variabilityThe small, irregular ups and downs of the baby's baseline heart rate seen on a fetal monitor tracing.

fetal stationHow far the presenting part of the fetus has moved down the birth canal, measured against the ischial spines of the pelvis.

fetusAn unborn baby from about the ninth week of development until birth.

fibrillationFast, uncoordinated twitching of muscle fibers, most often in the heart, so the muscle quivers instead of contracting together.

fibrinolysisThe body's process of breaking down a blood clot once it is no longer needed.

fibromyalgiaA long-term condition of widespread pain and tenderness in the muscles and soft tissues, with no damage to the joints.

fibrosisThe thickening and scarring of tissue, which replaces normal tissue with tough fibers.

fibrousMade of or containing tough threads (fibers), especially of connective tissue.

fibulaThe thin outer bone of the lower leg, beside the larger tibia.

fifth diseaseA common childhood viral illness caused by parvovirus B19, also called erythema infectiosum.

filtrationThe passing of fluid through a filter or membrane, which holds back larger particles; in the kidneys, the first step in making urine.

fingernailThe hard plate of keratin that covers the top of the end of each finger.

fingertipThe end of a finger.

FiO2Fraction of inspired oxygen: the percentage of oxygen in the air a person breathes in.