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Medical Dictionary - Letter: a

A&Dascending & descending
A&Walive and well
a-no, not, without, away from
AAAabdominal aortic aneurysm
AADantibiotic associated diarrhea
AALanterior axillary line
ab-away from
abdomenThe part of the body cavity below the thorax.
abdominal aortaThe part of the descending aorta passing through the diaphragm into the abdomen.
abdominal painDiscomfort, distress, or agony in the abdominal cavity. Can be acute or chronic. A significant clinical symptom.
abdominal quadrantsFour segments of the abdomen divided by horizontal and vertical lines intersecting at the umbilicus.
abdominal thrustsA maneuver for treating choking by using quick, forceful thrusts of fisted hands upward and inward toward the diaphragm. Commonly known as the Heimlich maneuver.
abdominal wallThe boundaries of the abdomen, consisting of multiple layers: skin, subcutaneous fat, superficial fascia, muscles, transversalis fascia, extra peritoneal fat, and the parietal peritoneum. Extends from the thoracic cage to the pelvis.
abdominoplastySurgical removal of excess abdominal skin and fat and tightening of the abdominal wall. Commonly called a tummy tuck.
abducens nerveA small cranial nerve which originates in the pons and sends motor fibers to the lateral rectus muscles of the eye. It provides horizontal eye movement control.
abductionMovement of a limb away from the midline or axis of the body.ab-duk´shun
aberrationA deviation from a normal condition or behavior.
ABGarterial blood gas
ABIankle-brachial index
ablat/oto remove, to destroy
ablationRemoval of tissue by vaporization, abrasion, freezing or other methods.ab-la´shun
ablation techniquesRemoval or disabling of body tissue by using hot liquids, microwave thermal heating, freezing, chemical ablation, and laser photoablation.
ablutionWashing the body.
ABOthree basic blood groups
abo blood groupA major blood classification system based on the presence or absence of two antigens, A and B. Type O occurs when neither A nor B is present and AB when both are present. A and B are genetic factors that determine the presence of enzymes for the synthesis of certain glycoproteins mainly in the red cell membrane.
abortifacientAn agent, usually a medication, that causes abortion.
aBParterial blood pressure
abrad/oto scrape, to wear away
abreactionAn emotional release after recollection of a repressed experience.
abscessAccumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection.
absenteeismChronic absence from work, school or other duties.
absorptionThe processes by which substances, tissue, cells, etc. take up or take in other substances or energy.
abstractA summary of the facts, ideas and opinions presented in articles, studies, literature or presentations.
ACadrenal cortex
-acpertaining to
AC (2)anticoagulent
ac (3)before a meal
acanth/othorny, sharp spine
acanthocytesErythrocytes with spiny projections giving the cell a thorny appearance.
acarboseA drug prescribed in treating type 2 diabetes mellitus. It retards the digestion of complex carbohydrates.
acaridaeFamily of mites frequently found in grain and flour.
accelerated idioventricular rhythmA type of automatic, not reentrant, ectopic ventricular rhythm with episodes lasting from a few seconds to a minute. The ventricular rate is 50 to 100 beats per minute.
accelerationA change in an object's rate of speed or direction.
accessory nerveEither of two cranial nerves which are important for swallowing, speech and some head and shoulder movements.
acclimatizationAdaptation of an organism to a new or changing environment.
accreditationCertification for voluntary compliance with standards established by non-governmental organizations.
acculturationProcess of accepting or assimilating cultural change.
ACE InhibitorDrug that lowers BP by inhibiting angiotensin converting enzyme (ACE) allowing increased blood flow
acebutololA beta blocker drug used to treat high blood pressure, irregular rhythms and angina pectoris.
acetabulumConcave surface of pelvis where the head of the femur liesas'ĕ-tab´u-lum
aceticHaving a sour property of vinegar or acetic acid.
acetoneA colorless liquid used as a solvent and an antiseptic. Present in urine.
achilles tendonThe tendon connecting the muscles in the back of the calf to the calcaneus (heel bone).
achlorhydriaAbsence of hydrochloric acid in gastric secretion.
achondroplasiaA disorder that is a form of short-limb dwarfism.
acid etchingPreparation of tooth surfaces with etching agents, such as phosphoric acid, to roughen the surface to increase adhesion.
acid-base balanceThe balance between acids and bases in the body fluids. The pH of the arterial blood provides an index for the total body acid-base balance.
acid/oacid, sour, bitter
acidosisA pathologic condition of acidity in body fluids and tissues. The two main categories are respiratory and metabolic acidosis.
ACLSadvanced cardiac life support
acneA common inflammation of the sebaceous glands and hair follicles.
acne conglobataSevere, chronic acne characterized by large, burrowing abscesses associated with disfigurement. Also called cystic acne.
acne keloidA disorder in which secondary pyogenic infection in and around pilosebaceous structures ends in keloid scarring. Often develops at the hairline on the back of the neck.
acquired immunodeficiency syndromeAn acquired defect of T-cell immunity associated with infection by the human immunodeficiency virus (HIV).
acr/oextremities, top
acrodermatitisChronic inflammation of the skin of the hands and feet. Caused by a parasitic mite. A manifestation of Lyme disease.
acromegalyA hormonal disorder that results when the pituitary gland produces excess growth hormone.ak'ro-meg´ah-le
acromioclavicular jointThe gliding joint formed by the outer extremity of the clavicle and the inner margin of the acromion process of the scapula. This joint has six ligaments.
acromionThe lateral extension of the spine of the scapula and the highest point of the shoulder.
acrophobiaFear of heightsak'ro-fo´be-ah
acrosomeThe cap-like structure covering the anterior portion of spermatozoon. It contains enzymes necessary for sperm penetration of the egg.
act-drive, do, act
ACTHadrenocorticotropic hormone
actin/oradiation, ray
actinic keratosisPre-cancerous patch of thick, scaly, or crusty skin secondary to extensive sun exposureak-tin'ik ker'ă-tō'sis
actinomycosisA chronic bacterial disease, often found on the abdomen, thorax and jaw. Characterized by lumpy, deep abscesses that discharge pus.
actomyosinA protein complex of actin and myosin occurring in muscle. It is the essential contractile substance of muscle.
acupunctureTherapy for treating pain and disease by inserting needles along specific pathways or meridians.
acutesevere; sudden in onset; lasting a short timeah-kūt´
acute respiratory distress syndromeA lung condition that causes low oxygen levels in the blood. It can be life threatening.
ADAlzheimer disease
-adtoward, in the direction of
ad-toward, increase
adams-stokes syndromeRecurring fainting spells caused by incomplete heart block.
ADDattention deficit disorder
Addison diseaseA rare disorder in which the adrenal glands do not produce enough of the hormones cortisol and/or aldosterone.
adductionMovement of a limb toward the midline or axis of the bodyah-duk´shun
adductorA muscle that moves a body part toward the midline or axis of the body.
adenitisInflammation of a lymph node resulting in swelling or pain.
adenocarcinomaA malignant epithelial tumor with a glandular growth pattern.
adenoidectomySurgical removal of the adenoids.
adenoidsA collection of lymphoid nodules on the posterior wall and roof of the nasopharynx.. ad'ĕ-noydz
adenomaA benign epithelial tumor with a glandular structure
adenovirusVirus responsible for upper respiratory tract infections, conjunctivitis, cystitis or GI infection.
ADHantidiuretic hormone
ADHDattention deficit-hyperactivity disorder
adhesionBands of scar tissue that can develop after´zhun
adiposeConnective tissue composed of fat cells.
adiposityThe amount of fat or lipid deposit at a site or an organ.
adjustment disordersMaladaptive reactions to a stressful event.
ADLactivities of daily living
adnexaAppendages of an organ (e.g. eyelids to the eyeball)ad-nek´sah
adolescenceA period beginning with puberty and ending at maturity. Usually from 11-13 years of age and ending at 18-20 years of age.
adren/oadrenal glands
adrenalPertaining to the adrenal glands, which are located atop of the kidneys.
adrenalectomySurgical removal of one or both adrenal glands.ə-drē′nə-lĕk′tə-mē
adrenalitisInflammation of the adrenal glands, ah-dre″nal-i´tis
adrenarcheA development stage when the adrenal glands mature, leading to the increased production of adrenal androgens, dehydroepiandrosterone and androstenedione. Adrenarche usually begins at about 7 or 8 years of age before the signs of puberty and continues throughout puberty.
adrenergic fibersNerve fibers liberating catecholamines at a synapse after an impulse.
adrenergic neuronsNeurons whose primary neurotransmitter is epinephrine.
adsorptionThe adhesion of gases, liquids, or dissolved solids onto a surface.
adultA person having attained maturity.
advanced cardiac life supportThe use of sophisticated methods and equipment to treat cardiopulmonary arrest. Advanced Cardiac Life Support (ACLS) includes the use of specialized equipment to maintain the airway, early defibrillation and pharmacological therapy.
adventitiaThe outermost covering of organs, blood vessels and other structures not covered by serosa.
AEabove elbow
AEDautomated external defibrillator
aerobicsSustained strenuous exercise that improves cardiovascular and respiratory fitness.
aerophagiaExcessive swallowing of air.ār″o-fa´jah
aerophagyExcessive swallowing of air caused by anxiety or improper eating habits.
AFatrial fibrillation
AFBacid-fast bacillus
affectThe emotional reaction to an experience or thought.
Afibatrial fibrillation
afibrinogenemiaA deficiency or absence of fibrinogen in the blood.
afterbirthThe placenta, umbilical cord and membranes that are expelled from the uterus after birth
aftercareHealth care provided to a patient after discharge.
ageusiaLoss of the sense of taste.
aggressionForceful verbal or physical behavior, or an overt attitude of hostility.
agit/orapidity, restlessness
agnosiaThe inability to comprehend or recognize the importance of various forms of stimulation.
-agoguesimulator, agent causing change
agonalRelating to conditions and struggles preceding death.
agonisticA muscle whose contraction causes movement of a body part. Also, a drug that combines with receptors to produce an action.
agoraphobiaObsessive, intense fear of open places or leaving home..
-agrasevere pain
agraphiaInability to write due to a cerebral injury or less commonly, due to emotional factors.
AHAAmerican Hospital Association
AHFantihemophilic factor
AIDSacquired immunodeficiency syndrome
AIHAautoimmune hemolytic anemia
airThe mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.
air sacsThin-walled spaces including the alveoli connected to one terminal bronchiole.
airwayTubular passages in the lungs through which air passes during breathing.
AIVRaccelerated idioventricular rhythm
AKabove the knee
akinetic mutismA syndrome characterized by a silent and inert state without voluntary motor activity despite alertness.
-alrelating to
alacrimaDry eye.
albin/owhite, deficient pigmentation
albinismGenetic disorders causing the skin, hair, or eyes to have little or no color.
albuminProteins found in egg whites, milk, blood, lymph, and other tissues and fluids. They are water soluble and coagulate upon heating.
albuminuriaThe presence of albumin in the urine, an indicator of kidney diseases.
albuterolA short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat asthma.
alcoholismA primary, chronic disease creating a physical dependence on alcohol. Genetic and environmental factors influence its development.
aldosteroneA hormone secreted by the adrenal cortex that acts on the kidneys to regulate electrolyte and water balance.
aldosteronismA disease that causes the adrenals to produce too much of the hormone´ter-ōn-izm″
alexiaInability to read despite preservation of the ability to write. The patient cannot recognize letters and words.
ALFassisted living facility
algidCold, clammy skin associated with some types of malaria.
alginateA salt of alginic acid extracted from marine kelp. Used for surgical dressings.
algorithmA step-by-step protocol for managing health care problems.
alienationLack of meaningful relationships with others, leading to estrangement.
alimentary canalThe passage for the digestion and absorption of food. Extends from mouth to anus.
alkaloidsOrganic nitrogenous bases produced by plants and used to create important, powerful drugs.
alkalosisA condition of high alkalinity of blood and other body fluids.
ALLacute lymphocytic leukemia
allergenAntigen-type substance that produce immediate´er-jen
allergyHypersensitive reaction to common substances that are in the environment or digested. Also, an acquired sensitivity to certain drugs.
allied health personnelHealth care workers specially trained and licensed to provide patient services in specialties such as physical therapy, laboratory sciences, dental hygiene and emergency services.
alloantigenAn antigen that occurs in some but not all members of a species.
allograftTissues, cells, or organs transplanted between genetically different individuals of the same species.
allopathyA medical therapy system in which a disease is treated by creating a second condition in the body that opposes the disease.
allopurinolA xanthine oxidase inhibitor that decreases uric acid production. Used to treat gout and kidney stones.
aloeThe dried juice of aloe plant leaves. Used to treat minor wounds, burns and skin irritations.
alopeciaA disorder in which the immune system attacks hair follicles in the″o-pe´shah
alphavirusA group of small Toga viruses. Can be transmitted from mosquitoes to humans, causing several types of encephalitis.
alprazolamA compound used to treat anxiety.
alprostadilA potent vasodilator agent that increases peripheral blood flow.
altitude sicknessMultiple symptoms associated with reduced oxygen at high altitude. These symptoms include headache, nausea, fatigue, difficulty sleeping, tachycardia and shortness of breath.
alve-channel, cavity
alveoliAir sacs in the lung which allow exchange of blood oxygen and carbon·vē′ō·lī
alveolitisAn inflammation of the alveoli. Caused by inhalation of an allergen.
Alzheimer diseaseType of dementia that causes problems with memory, thinking, and behavior.awltz'hī-mĕr
AMAAmerican Medical Association
amalgamA mixture of mercury, silver and other metals used in dentistry.
amanitaA genus of mushrooms. Some species are poisonous.
amantadineAn antiviral agent used to treat influenza A. Also used as an antiparkinsonian agent.
amaurosisPartial or complete blindness caused by a disease.
amberA hard, yellowish fossil resin from pine trees.
ambi-both, both sides, around
ambientPertaining to the environment of an organism or mechanism.
ambivalenceConflicting feelings or attitudes towards a person, object or idea.
ambly/odull, dim
amblyopiaDecrease of vision due to abnormal development during childhood. Also known as lazy″ble-o´pe-ah]
ambulanceA vehicle for transporting patients for treatment.
ambulatoryAble to walk.
amebaA large genus of protozoa found in water and moist conditions. Several species may be parasitic in humans.
amebiasisInfection with ameba. Widespread condition in tropical countries.. An asymptomatic condition in most people but diseases ranging from diarrhea to dysentery.
amebicideA drug or other agent which destroys ameba, particularly parasitic species.
ameloblastomaA fast growing epithelial tumor of the jaw.
amelogenesisThe formation of dental enamel by ameloblasts.
amenorrheaAbsence of menstruation.a-men″o-re´ah
ametropiaAn eye problem caused by faulty″ĕ-tro´pe-ah
AMIacute myocardial infarction
amino acidA group of organic compounds that contain an amino and a carboxyl group.
aminoglycosideAntibiotic that prevents bacteria from producing proteins. Requires monitoring due to side-effects.
aminophyllineA bronchodilator. Used to treat asthma and COPD.
AMLacute myelogenous leukemia
amnesiaLoss of memory due to brain injury or emotional trauma.
amni/oamnion, sac around embryo
amniocentesisDiagnostic test for chromosomal abnormalities and fetal infections. A small amount of fluid is removed from the amniotic″ne-o-sen-te´sis
amniotic fluidA clear, yellowish liquid that surrounds the fetus, protecting it from injury.
amobarbitalA barbiturate sedative-hypnotic.
amoxicillinAn oral semisynthetic penicillin antibiotic.
ampereA measure of electrical current. One ampere (amp) is equal to the current flowing through a one ohm resistance when an electrical potential of one volt is applied.
amphetamineA powerful group of drugs that stimulate the central nervous system. Amphetamines reduce feelings of fatigue and increase alertness.
amphi-both sides
ampho-both sides, double
ampicillinSemisynthetic penicillin that functions as a broad-spectrum antibiotic.
amputationThe removal of a limb or other body appendage.
amylaseA group of enzymes that help digest starches.
amyloidosisA group of infectious diseases cause abnormal protein folding and deposition of amyloid. These amyloid deposits can enlarge and displace normal tissue, impairing function.
amyloseThe soluble constituent of starch.
amyotrophic lateral sclerosisA neurological disease causing muscle weakness and impacting physical function. Commonly called ALS.ā′mī·ōtrof′ik
-anpertaining to
an-not, without, away from
an/oanus, ring
ANAantinuclear antibody
ana-up, apart, again
anabolic steroidA compound derived from testosterone or synthetically that stimulates development of muscle mass, strength, and power.
anacrotismA secondary notch in the pulse curve, obtained in a pulse tracing.
anaerobicTaking place without oxygen.
anal canalThe terminal segment of the large intestine ending at the anus.
analgesiaWithout pain or decreased pain.
analgesicsA compound that relieves pain.
anaphylaxisA severe immune system reaction to a previously encountered antigen. Can sometimes be″ah-fi-lak´sis
anaplasiaLoss of structural differentiation and useful function of neoplastic cells. Typical of malignant tumors.
anasarcaMassive swelling (edema) of the legs, truck and genitalia. Occurs in congestive heart failure, renal disease or liver failure.
anastomosisA surgical connection between two structures.ah-nas″to-mo´sis
anatomyThe study of the structure of organisms.
anconeusA small triangular muscle behind the elbow. Its function is to extend the forearm.
androgenSteroid hormones that stimulate development of male reproductive organs, beard growth, voice changes and muscles.
androidPertaining to something human.
androsteroneA metabolite of testosterone or androstenedione.
anemiaBlood lacks enough erythrocytes (RBC) or hemoglobin.ah-ne´me-ah
aneroid A kind of barometer operated by the movement of the elastic lid of a box exhausted of air.
anesthesiaThe loss of feeling or sensation, particularly pain.
anesthesiologyA specialty concerned with the study of anesthetics and anesthesia.
anestheticMedication that causes temporary loss of″es-thet´ik
anestheticsAgents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act generally or locally.
anetodermaBenign dermatosis caused by a loss of dermal elastic tissue resulting in localized sac-like areas of flaccid skin.
aneurysmA sac-like dilatation of a blood vessel wall. It indicates a weak spot in the wall which may rupture. an´u-rizm
angerA strong emotional feeling of displeasure aroused by being interfered with, injured or threatened.
angi/oblood or lymph vessel
angina pectorisChest pain, pressure, or squeezing, often due to ischemia of the heart´jĭ-nah pĕk′tər-ĭs
angiocardiographyRadiography of the heart and great vessels after injection of a contrast medium.
angioedemaSwelling involving the deep dermis, subcutaneous, or submucosal tissues, representing localized edema. It often occurs in the face, lips, tongue, and larynx.
angiographyAn x-ray study of blood vessels after injection of a contrast medium. an″je-og´rah-fe
angiokeratomaA benign vascular, horny neoplasm of the skin often found on the legs and feet.
angiomaA usually benign tumor consisting of blood vessels and lymph nodes.
angiomyomaA benign tumor consisting of vascular and smooth muscle elements.
angioplastyRepair of a blood vessel such as widening a narrowed artery or vein. This procedure is normally performed using catheterization. an´je-o-plas″te
angioscopeAn endoscope used for viewing the interior of blood vessels.
angiostenosisAbnormal narrowing of a blood'jē-ō-stĕ-nō'sis
angiotensinA family of peptides in the blood that causes vasoconstriction and increased blood pressure.
angstromA unit of length equal to 0.1 nanometer.
anhedoniaInability to experience happiness or pleasure. It is a symptom of many psychotic disorders.
anhidrosisAbsence of sweating in an environment appropriate for sweating.
anionNegatively charged ion.
anisocoriaUnequal pupil sizes. Affects 20% of the″so-kor´e-ah
ankleThe region between the foot and leg.
ankle brachial indexThe ankle-arm index. This is the ratio of the higher of the two ankle systolic blood pressures divided by the higher of the two arm systolic pressures. It is a predictor of peripheral arterial disease.
ankyl/obent, stiff
ankylosisFixation and immobility of a joint. ang″kĭ-lo´sis
anodontiaCongenital absence of most or all teeth.
anomalyA variation from normal, particularly congenital defect
anomiaAn inability to name people and objects that are correctly comprehended.
anorexiaThe lack or loss of appetite with an inability to eat.
anorexia nervosaAn eating disorder characterized by a loss of appetite and an excessive fear of becoming″o-rek´se-ah nûr-vō′sah
anosmialoss or impairment of the sense of smell. It can be temporary or permanent.
anovulationSuspension or cessation of ovulation by the ovaries.
anoxiaAbsence of oxygen in body tissues despite adequate blood´se-ah
antacidsSubstances that neutralize acidity in the stomach.
antagonistA person, muscle or drug that opposes another.
antazolineA short acting antihistamine
ante-forward, before
antegradeMoving forward or moving in the direction of blood or urine flow.
antepartal careHealth care provided during pregnancy.
anterior chamberThe space between the cornea and the iris, filled with aqueous humor.
anterior cruciate ligamentA strong ligament of the knee that extends from the anterior intercondylar area of the tibia to the posterior part of the medial surface of the lateral condyle of the femur. Responsible for controlling stability during knee rotation.
anthelminticsAgents that destroy or prevent development of parasitic worms.
anthrac/ocarbon, coal
anthracosisA chronic lung disease caused by inhaled coal dust. Occurs in coal miners but also in tobacco smokers.
anthraxAn acute infectious disease of hoofed animals and humans. Infection in humans often involves the skin , lungs or gastrointestinal tract.
anthrop/ohuman life
anti-inflammatoryReducing inflammation.
antibioticsAn infection fighting protein made by blood plasma cells in response to an antigen. It helps destroy bacteria, viruses and toxins.
antibodiesImmunoglobulin molecules produced in lymphoid tissue that attack the antigen that induced their synthesis.
antibodyProtein produced by B cells as primary immune defense.
anticoagulantsAgents that slow coagulation and prevent blood clotting.
anticonvulsantsDrugs used to prevent seizures or reduce their severity.
antidepressantsDrugs that prevent or relieve depression.
antidiabeticDrugs that help control diabetes mellitus.
antidiarrhealA drug or food for treating diarrhea.
antidiuretic hormoneA hormone produced by the hypothalamus and stored in the pituitary gland. This hormone controls the amount of water excreted in the″ti-di″u-ret´ik
antidromicConducting nerve impulses in a direction opposite from normal.
antiemeticsDrugs used to prevent nausea or vomiting.
antifibrinolyticPreventing the breakdown of a blood clot or thrombus.
antifungalSubstances that destroy″ti-fung´gal
antigenSubstances that are recognized by the immune system and induce an immune´tĭ-jen
antigensSubstances that are recognized by the immune system and induce an immune reaction.
antihistamineAn agent that inhibits the actions of a histamine.
antihypertensiveDrugs used to reduce high blood pressure.
antimitoticDrugs that arrest cell division.
antioxidantSubstances that inhibit oxidation of a substance.
antiparasiticA drug used to treat or prevent parasitic infections.
antiperspirantsAgents that are put on the skin to reduce sweating.
antipruriticAn agent that relieves itching. Usually topical.
antipsychoticAn agent used to control severe mental disorders.
antipyreticA drug used to reduces fever.
antisepsisThe destruction of germs causing disease.
antisocial A personality disorder characterized by a disregard for individual rights or laws.
antispasmodicA drug used to treat smooth muscle spasms in the digestive system, uterus or urinary tract.
antithyroidAn agent used to treat hyperthyroidism.
antitoxinsAntisera from immunized animals that is purified and used as a passive immunizing agent against specific bacterial toxins.
antitussive agentsCough medicine that acts centrally on the medullary cough″ti-tus´iv
antiviralDestroying a virus or suppressing replication.
antr/oantrum, cavity
antrumA cavity or chamber.
anuriaAbsence of urine formation.ah-nu´re-ah
anusThe distal opening of the alimentary canal, lying in the fold between the buttocks.
anxietyFeeling or emotion of dread, apprehension, or fear without apparent stimulus.
anxiety disordersA group of mental disorders characterized by feelings of anxiety and fear.
AODMadult-onset diabetes mellitus
aortaThe main trunk of the systemic arteries originating at the heart's left ventricle.
aortic aneurysmAn abnormal balloon or sac-like dilatation in the aortic wall.ā-ōr'tik an'yūr-izm
aortic coarctationA congenital heart abnormality where the aorta is narrowed.ā-ōr'tik kō-ahrk-tā'shŭn
aortic stenosisNarrowing of the aortic valve opening, reducing outflow from the left ventricle into the aorta.ā-ōr'tik stĕ-nō'sis
aortic valveThe valve between the left ventricle and the aorta. It prevents back flow of blood into the left ventricle.
aortic valve regurgitationBack flow of blood from the aorta into the left ventricle. re-ger″jĭ-ta´shun
APAantipernicious anemia factor
apacheAn acronym for Acute Physiology and Chronic Health Evaluation, a scoring system used for classifying the severity of illness in critically ill patients.
apathyLack of emotion or emotional expression; disinterest.
apexThe tip of an organ.
Apgar scoreNewborn health assessment score (0-10).
Two points each: Appearance of skin color, Pulse, Grimace, Activity, Respiration.
aphakiaAbsence of the eye's lens.ah-fa´ke-ah
aphasiaImpairment of language or speech comprehension.ah-fa´zhah
-apheresisseparation, removal
aphoniaInability of the larynx to produce speech sounds. a-fo´ne-ah
aphrodisiacAn agent that stimulates sexual desire.
apicalPertaining to the tip or apex of a structure.
aplasiaDefective development of an organ or tissue.
aplastic anemiaA condition in which bone marrow doesn't produce sufficient blood elements. ah-ne´me-ah
apneaA temporary cessation of spontaneous respiration.
apo-separate, away from
apocrine glandsSweat glands that only occur in hairy parts of the body.
apophysisAn outgrowth or projection from a bone.
apoptosisProgrammed cell death resulting in the orderly removal of cells.
appendectomySurgical removal of the appendix.ap″en-dek´to-me
appendicitisAcute inflammation of the vermiform appendix.
appendixA worm-like blind tube extension from the cecum.
appetiteNatural recurring desire, e.g. for food.
apraxiaDisorders characterized by the inability to make skilled, purposeful movements due to a cerebral disease.
aprepitantA drug used to treat chemotherapy induced nausea.
aptitude testsStandardized tests designed to predict an individual's learning ability or performance.
aquaphobiaAn irrational fear of water.
aqueous humorThe clear, watery fluid circulating in the anterior and posterior chambers of the eye.
-arpertaining to
arachnoidA delicate membrane covering the brain and spinal cord. It lies between the pia mater and the dura mater.
arachnoiditisAcute or chronic inflammation of the arachnoid membrane, resulting in pain and neurological abnormalities.
arborA tree-like structure with branching.
arbovirusViruses transmitted by saliva of insects, bats and rodents.
ARCAIDS-related complex
arch-beginning, origin, first
ARDSacute respiratory distress syndrome
areolaA ring of pigmented skin surrounding a nipple.ah-re´o-lah
ARFacute renal failure
argonAn odorless, colorless, inactive gas with atomic number 18.
argyriaA permanent ashen-gray discoloration of the skin, conjunctiva, and internal organs due to ingestion of or exposure to silver salts.
armThe superior part of the upper limb between the shoulder and the elbow.
ARMDage-related macular degeneration
aromatherapyThe use of fragrances and plant oils to improve physical, mental, and emotional well-being.
arousalA state of alertness due to stimulation.
arrhythmiaAbnormal heartbeat rhythm. To learn more, visit arrhythmia page at Practical Clinical Skills website.ah-rith´me-ahz
arsenicA shiny gray element with atomic symbol As, atomic number 33. Most forms are toxic.
arterial blood gasesA test that measures the levels of oxygen, carbon dioxide and acidity (pH) in the blood. Some blood gases devices make additional measurements available.
arteriesThe vessels carrying blood away from the heart.
arteriol/osmall artery
arteriolesThe smallest divisions of the arteries located between the muscular arteries and the capillaries.
arteriolosclerosisThickening of the walls of small arteries or arterioles.
arteriosclerosisThickening and stiffening of arterial walls.ahr-te″re-o-sklĕ-ro´sis
arteriostenosisNarrowing of arterial walls.ahr-te″re-o-stĕ-no´sis
arteritisinflammation of one or more arteries.
arthralgiaJoint pain.ahr-thral´jah
arthritisInflammation of joints, characterized by pain, swelling and diminished range of motion.
arthrocentesisAspiration of fluid (e.g., synovial fluid) from a joint cavity.
arthrodesisThe surgical fixation of a joint by a procedure designed to accomplish fusion of the joint surfaces by promoting the proliferation of bone cells.ahr″thro-de´sis
arthrographyImaging of a joint, usually after injection of a contrast medium.
arthrolysisSurgical restoration of mobility in stiff, ankylosed joints.ahr-throl´ĭ-sis
arthroplastySurgical reconstruction of a joint to relieve pain or restore motion.
arthropodA member of the phylum Arthropoda, composed of organisms having a hard, jointed exoskeleton and paired jointed legs. It includes insects, mites, ticks and spiders.
arthroscopyExamination, therapy and surgery of a joint using an endoscope.ahr-thros´kah-pe
articulationThe junction of two or more bones. Also, forming sounds into meaningful speech.
artifactsAnything artificially made. An unwanted problem with a medical imaging technique.
artificial limbsProsthetic replacements for arms and legs.
-arypertaining to
ASaortic stenosis
ASAacetylsalicylic acid
asbestosisLung disease characterized by interstitial fibrosis. Caused by inhalation of asbestos″bes-to´sis
ASCatypical squamous cells
ASC-USatypical squamous cells of undetermined significance
ascitesAbnormal accumulation of free fluid within the peritoneal cavity. ah-si´tēz
ascorbic acidA water soluble compound. As vitamin C, it naturally occurs in citrus fruits and many vegetables.
ASDatrial septal defect
aspartameArtificial sweeter, metabolized as phenylalanine and aspartic acid.
asperger syndromeA developmental disorder whose essential features are persistent impairment in reciprocal social interactions, and restricted, repetitive patterns of behavior, interests, or activities and impairment in language and communications skills.
aspermiaA condition characterized by the complete absence of semen.
asphyxiaCondition caused by lack of oxygen, leading to loss of consciousness and death. Causes include drowning, suffocation, choking and inhaling carbon´se-ah
aspirinAn analgesic, anti-inflammatory and antipyretic agent. It also reduces the risk of vascular thrombosis.
assaultA violent physical or verbal attack.
assertivenessStrongly insistent, self-assured behavior.
assimilationThe transformation of food into living tissue.
astasiaThe inability, without physical cause, to stand or sit without assistance.
asthmaChronic bronchial inflammatory disorder. Characterized by breathing difficulty, wheezing, coughing and´mah
astigmatismA common and generally easily treatable imperfection in the curvature of the eye. ah-stig´mah-tizm
astringentA drug, usually topical, that cause the contraction of tissues. Used for controlling bleeding or secretions.
astrocyteA large, star shaped cell. Found throughout the central nervous system.
astrocytomaA type of brain tumor.
asystoleComplete absence of cardiac output and electrical activity in the heart.a-sis´to-le
ataxiaInability to coordinate voluntary muscle movements, not due to muscle weakness.ah-tak´se-ah
atcaround the clock
atelectasisPartial or complete failure of a lung to expand due to alveoli deflation. Can occur after surgery, trauma,′ilek′təsis
ateliosisA form of dwarfism.
atelo-incomplete, imperfect
ather/oplaque, soft fatty deposit
atherectomyEndovascular procedure for removing atheromatous plaque by a cutting or rotating catheter.
atheromaA thickening and loss of elasticity of arterial walls due to plaque deposits. Also called atherosclerosis.ath″er-o´mah
atherosclerosisA thickening and loss of elasticity of arterial walls due to plaque deposits. ath″er-o″sklĕ-ro´sis
athetosisSlow, continuous slow, flowing involuntary movements of the fingers, toes, tongue and face. Often a form of cerebral palsy. While impairing speech, intelligence in often unaffected.
ATLadult T cell leukemia
atmosteam, vapor
atonicWithout normal muscle tone or strengthā-ton'ik
atorvastatinA drug used to reduce the levels of cholesterol and triglycerides in the blood.
atresiaThe absence or abnormal narrowing of a body opening or duct.
-atresiaclosure, occlusion
atriaThe upper chambers of the heart which receive blood flow from the body.a´tre-ah
atrial fibrillationAbnormal cardiac rhythm characterized by rapid, uncoordinated firing of electrical impulses in the atria. Increases risk of stroke and heart disease.ā′trē·əl
atrial flutterA very rapid, irregular heart rhythm. A common form of tachyarrhythmia. ā′trē·əl
atrioventricular nodeA small group of specialized muscle fibers located on the floor of the right atrium. It regulates electrical signals to the ventricles, preventing rapid conduction and ensuring that the atria have emptied.a″tre-o-ven-trik´u-ler
atrium(of the heart). Either of the two upper chambers of the heart.
atrophyDiminished size or wasting away of body tissue, for example´ro-fe
attentionMentally focusing on a specific object, issue or activity. The act of concentrating.
attenuationThe reduction or dilution of disease producing ability.
attitude1) A position or posture of the body. 2) A way or manner of behaving.
attritionWearing away.
atypicalUnusual. Not representative of a type or group.
audiologyThe study of hearing and hearing impairment.
audiometryA noninvasive test that measures the ability to hear different tones and'dē-om'ĕ-trē
auditA formal review of data or records.
augmentationThe process of increasing in size or amount.
AULacute undifferentiated leukemia
auralRefers to the ear or´ral
auranofinA drug for treating rheumatoid arthritis.
auscultationListening for body sounds usually with a stethoscope.
autismA group of developmental disabilities that can cause significant social, communication and behavioral´tizm
auto-self, same
autoantibodyAn antibody that react with self-antigens of the organism that produced them.
autoantigensEndogenous tissue constituents that have the ability to interact with autoantibodies and cause an immune response.
autograftTransplant comprised of an individual's own tissue, transferred from one part of the body to another.
autoimmuneDisorder of the immune system in which an immune response is created against the body's own tissues.
autoimmune disorderImmune system attacks on healthy cells by mistake.
autoimmunityProcess whereby the immune system reacts against the body's own tissues.
autologousOne individual being both donor and recipient (e.g. blood).aw-tol´ah-gus
autolysisThe disintegration of tissues or cells by intracellular enzymes.
automatismAutomatic, mechanical, and apparently undirected behavior which is outside of conscious control.
autonomicThe ability to function without external influence.
autonomic nervous systemThe part of the nervous system that regulates involuntary body functions. The enteric nervous system; parasympathetic nervous system; and sympathetic nervous system taken together.
autonomyAbility to function independently. Self-governing.
autophagiaBiting or eating one's own flesh.
autopsyPostmortem examination of the body to determine the cause of death.
autosomeAny chromosome that is not a sex chromosome and that occurs in pairs in somatic cells.
autosuggestionSuggestion coming from the subject himself.
autotrophicSelf nourishing. The processes by which organisms use inorganic substances such carbon dioxide and inorganic nitrogen as nutrient sources.
avascularAn area of the body lacking adequate blood vessels or blood supply.
AVBatrioventricular block
aversion therapyA treatment that suppresses undesirable behavior by simultaneously exposing the subject to unpleasant consequences.
avian influenzaA highly contagious disease of poultry and other birds, caused by strains of influenza A virus.
avitaminosisDisease caused by vitamin deficiency.
avoidanceA psychological or physical defense mechanism for avoiding a noxious experience.
AVRaccelerated ventricular rhythm
axialPertaining to an axis.
axonNerve fiber that conduct impulses away from the neuron cell body.
azoospermiaA complete absence of sperm in the ejaculate.a-zo″o-sper´me-ah
azotemiaA biochemical abnormality referring to an elevation of blood urea nitrogen and creatinine.