Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

Ewing tumor
Ewing sarcoma.

ex vivo
(eks ve´vo) outside the living body; denoting removal of an organ (such as the kidney) for reparative surgery, after which it is returned to the original site.

exacerbation
(eg-zas″әr-ba´shәn) increase in severity of a disease or any of its symptoms.

exact test
a statistical test based on the actual probability distribution of the data in the study, rather than on an approximation of it.

exanthem
(eg-zan´thәm) a skin eruption or rash. a disease in which skin eruptions or rashes are a prominent manifestation. exanthem subitum exanthema subitum.

exanthema
(eg″zan-the´mә) pl. exanthemas, exanthem´ata Greek word meaning a rash; see exanthem. exanthema subitum a common acute disease caused by infection with the herpesvirusRoseolovirus. It usually occurs in children under two years old, coming on suddenly and disappearing in 3 to 5 ...

exanthematous
(eg″zan-them´ә-tәs) characterized by or of the nature of an eruption or rash.

exanthematous disease virus
any of a group of dermotropic viruses, including poxviruses, causing exanthematous disease in humans and other animals.

exanthematous fever
eruptive fever.

exarticulation
(eks″ahr-tik″u-la´shәn) disarticulation.

excavation
(eks″kә-va´shәn) the act of hollowing out. a hollowed-out space, or pouchlike cavity. atrophic excavation cupping of the optic disk, due to atrophy of the optic nerve fibers. excavation of optic disk , physiologic excavation&...

excavator
(eks´kә-va″tәr) a scoop or gouge for surgical use. Excavator.

excess
(ek-ses´) (ek´ses) an amount more than is normal or necessary.

exchange
(eks-chānj´) the substitution of one thing for another. to substitute one thing for another. alveolar gas exchange the passage of oxygen and carbon dioxide in opposite directions across the alveolocapillary membrane. plasma exchange the r...

exchange transfusion
transfusion in a newborn infant of packed red blood cells or fresh whole blood that is type O, Rh-negative, and previously cross-matched with the mother's serum, or Rh negative blood of the same type as the newborn's. Rh negative blood is used because, even though the newborn may have Rh positive blood, maternal antibodie...

excimer laser
a laser with rare gas halides as the active medium, used in ophthalmological procedures and angioplasty. The beam is in the ultraviolet spectrum and penetrates tissues only a small distance; it breaks chemical bonds instead of generating heat to destroy tissue.

excipient
(ek-sip´e-әnt) any more or less inert substance added to a drug to give it suitable consistency or form; called also vehicle.

excise
(ek-sīz´) to remove by cutting.

excision
(ek-sizh´әn) removal of a portion or all of an organ or other structure. Called also resection.

excisional biopsy
removal of biopsy tissue by surgical cutting, such as a lumpectomy.

excitability
(ek-sīt″ә-bil´ĭ-te) irritability.

excitable cell
a cell that can generate an action potential at its membrane in response to depolarization and may transmit an impulse along the membrane; most are nerve cells or muscle cells, although other kinds of cells have also been shown to be excitable.

excitant
(ek-sīt´әnt) stimulant.

excitation
(ek″si-ta´shәn) an act of irritation or stimulation; a condition of being excited or of responding to a stimulus; the addition of energy, as the excitation of a molecule by absorption of photons. anomalous atrioventricular excitation Wolff-Parkinson-White syndrome. ...

excitation wave
an electric wave flowing from a muscle just previous to its contraction.

excited skin syndrome
nonspecific cutaneous hyperirritability of the back, sometimes occurring when multiple positive reactions are elicited in patch tests screening a battery of substances. Called also angry back.

excited state
the condition of a nucleus, atom, or molecule produced by the addition of energy to the system as the result of absorption of photons or of inelastic collisions with other particles or systems.

excitement
(ek-sīt´ment) response to stimuli, often used specifically to denote excessive responsiveness to stimuli, particularly of an emotional nature, and often leading to impulsive activity. psychomotor excitement psychomotor acceleration.

excitomotor
(ek-si″to-mo´tәr) tending to produce motion or motor function; an agent that so acts.

excitor nerve
a nerve that transmits impulses resulting in an increase in functional activity.

excitoreflex nerve
an autonomic nerve that produces reflex action.

excitosecretory
(ek-si″to-sә-kre´tә-re) producing increased secretion.

excitovascular
(ek-si″to-vas´ku-lәr) stimulating the circulatory system.

exclave
(eks´klāv) a detached part of an organ. The accessory thyroid is an exclave of the thyroid.

exclusion
(eks-kloo´zhәn) a shutting out or elimination. surgical isolation of a part, as of a segment of intestine, without removal from the body.

exclusion chromatography
gel filtration chromatography.

excoriated acne
a superficial type seen most often in girls and young women, caused by compulsive picking and squeezing of tiny (or nonexistent) facial lesions; it produces secondary lesions that can leave scars.

excoriation
(eks-ko″re-a´shәn) scratch (def. 3).

excrement
(eks´krә-mәnt) feces. excretion (def. 2).

excrementitious
(eks″krә-mәn-tish´әs) pertaining to excrement. fecal.

excrescence
(eks-kres´әns) an abnormal outgrowth; a projection related to a disease or pathologic condition. adj., excres´cent., adj.

excreta
(eks-kre´tә) excretion (def. 2).

excrete
(eks-krēt´) to throw off or eliminate, as waste matter, by a normal discharge. Called also void.

excretion
(eks-kre´shәn) the act, process, or function of excreting. Ordinarily, what is meant by excretion is defecation, the evacuation of feces. Technically, excretion can refer to the expulsion of any matter, whether from a single cell or from the entire body, as well as to the matter excreted. waste mater...

excretory duct
one through which the secretion is conveyed from a gland.

excursion
(eks-kur´zhәn) a range of movement regularly repeated in performance of a function, such as excursion of the jaws in mastication. adj., excur´sive, adj. . lateral excursion sideward movement of the mandible between the position of closure and the position in which cusps of o...

excystation
(ek″sis-ta´shәn) escape from a cyst or envelope, as in that stage in the life cycle of parasites occurring after the cystic form has been swallowed by the host.

exemestane
(ek″sә-mes´tān) an aromatase inactivator structurally related to androstenedione; used as an antineoplastic in the treatment of advanced breast carcinoma in postmenpausal women, administered orally.

exenteration
(ek-sen″tәr-a´shәn) extensive evisceration of organs and nearby structures. in ophthalmology, removal of the entire contents of the orbit. pelvic exenteration removal of the organs and adjacent structures of the pelvis.

exercise
(ek´sәr-sīz) performance of physical exertion for improvement of health or correction of physical deformity.

exercise intolerance
limitation of ability to perform work or exercise at normally accepted levels, as measured in exercise testing.

exercise stress tests
tests used in exercise testing.

exercise testing
techniques for evaluating circulatory response to physical stress, with continuous electrocardiographic monitoring during physical exercise. The objective is to increase the intensity of physical exertion until a target heart rate is reached or signs of cardiac ischemia appear. Called also stress testing. Common forms of exerci...

exercise thallium scintigraphy
myocardial perfusion using thallium 201 as a tracer and performed in conjunction with an exercise stress test.

exergonic
(ek″sәr-gon´ik) accompanied by the release of free energy.

exertional headache
one occurring after exercise.

exflagellation
(eks-flaj″ә-la´shәn) the protrusion or formation of flagelliform microgametes from a microgametocyte in malarial parasites and some related sporozoa.

exfoliatin
(eks-fo″le-a´tin) an erythrogenic epidermolytic, heat-stable, acid-labile exotoxin produced by certain strains of Staphylococcus aureus (phage group II), which causes intraepidermal separation by disturbing the adhesive forces between cells in the stratum granulosum to give rise to the clinical manifestations of s...

exfoliation
(eks-fo″le-a´shәn) a falling off in scales or layers. the removal of scales or flakes from the surface of the skin. the normal loss of primary teeth after loss of their root structure. adj., exfo´liative., adj. lamellar exfoliation of the newborn ...

exfoliation syndrome
degenerative alterations of anterior ocular tissues, first presenting as disturbances of pigmentary distribution in the iris, with partial atrophy of the iris pigmentary epithelium and deposition of liberated pigment granules on the lens capsule, papillary margin, ciliary body, and zonule. In later stages, gray, flakelike...

exfoliative dermatitis
widespread erythema, desquamation, scaling, and itching of the skin and loss of hair; it may result from internal medication with such drugs as penicillin, quinine, sulfonamides, gold salts, and iodides.

exhalation
(eks″hә-la´shәn) the act of breathing out; called also expiration and halitus.

exhaustion
(eg-zaws´chәn) a state of extreme mental or physical fatigue. the state of being drained, emptied, consumed, or used up.

exhaustion atrophy
atrophy of an endocrine organ from prolonged overwork of it.

exhibitionism
(eg″zĭ-bish´ә-niz-әm) a paraphilia characterized by repeated acts of exposing the genitals to an unsuspecting stranger to achieve sexual excitement, with no attempt at further sexual activity with the stranger. It is usually seen in males, often those unable for physical or psychologic reaso...

exhibitionist
(eg″zĭ-bish´ә-nist) a person who indulges in exhibitionism.

exit block
heart block characterized by failure of an expected impulse to emerge from its focus of origin and propagate; this usually occurs with a parasystolic focus, but is also seen with sinus, junctional, and ventricular rhythms. In cardiac pacing it means that the pacemaker stimulus is not of sufficient amplitude to stimulate the hea...

exocardia
(ek″so-kahr´de-ә) congenital displacement of the heart; ectocardia.

exocrine
(ek´so-krin) secreting externally via a duct, as opposed to endocrine. denoting such a gland or its secretion.

exocrine gland
a gland that discharges its secretions through ducts opening on internal or external surfaces of the body; examples include the lacrimal, salivary, sebaceous, sweat, gastric, intestinal, and mammary glands, as well as the liver, pancreas, and prostate.

exocytosis
(ek″so-si-to´sis) the discharge from a cell of particles that are too large to diffuse through the wall; the opposite of endocytosis. the aggregation of migrating leukocytes in the epidermis as part of the inflammatory response.

exodeviation
(ek″so-de″ve-a´shәn) a turning outward; in ophthalmology, exotropia.

exoenzyme
(ek″so-en´zīm) an enzyme that acts outside the cell that secretes it.

exoerythrocytic
(ek″so-ә-rith″ro-sit´ik) occurring or situated outside the red blood cells (erythrocytes), a term applied to a stage in the development of malarial parasites that takes place in cells other than erythrocytes.

exogamy
(ek-sog´ә-me) fertilization by union of cells not derived from the same parent cell. adj., exog´amous, adj. .

exogenous
(ek-soj´ә-nәs) developed or originating outside the organism, as exogenous disease. growing by additions to the outside.

exogenous hyperlipemia
elevated plasma levels of chylomicrons (lipoproteins from dietary sources); this usually refers to a specific hereditary type of hyperlipoproteinemia.

exogenous infection
that caused by organisms not normally present in the body that have gained entrance from the environment.

exomphalos
(ek-som´fә-los) hernia of the abdominal viscera into the umbilical cord. umbilical hernia.

exonuclease
(ek″so-noo´kle-ās) an enzyme that cleaves single mononucleotides from the end of a polynucleotide chain.

exopeptidase
(ek″so-pep´tĭ-dās) a proteolytic enzyme whose action is limited to terminal peptide linkages.

exophoria
(ek-so-for´e-ә) heterophoria in which there is deviation of the visual axis of an eye away from that of the other eye in the absence of visual fusional stimuli. adj., exopho´ric, adj. .

exophthalmic goiter
goiter accompanied by protrusion of the eyeballs, as in Graves disease.

exophthalmometry
(ek″sof-thәl-mom´ә-tre) measurement of the extent of protrusion of the eyeball in exophthalmos. adj., exophthalmomet´ric, adj. .

exophthalmos
(ek″sof-thal´mos) abnormal protrusion of the eye, resulting in a characteristic stare; it is usually due to hyperthyroidism but is occasionally caused by an infection of the eye or a tumor behind the eye. adj., exophthal´mic., adj.

exophytic
(ek″so-fit´ik) growing outward; in oncology, proliferating externally or on the surface epithelium of an organ or other structure in which the growth originated.

exophytic carcinoma
a malignant epithelial neoplasm with marked outward growth like a wart or papilloma.

exorbitism
(eg-sor´bĭ-tiz-әm) protrusion of the eyeball.

exoserosis
(ek″so-se-ro´sis) an oozing of serum or exudate.

exoskeleton
(ek″so-skel´ә-ton) an external hard framework to the bodies of certain animals, derived from the ectoderm, such as a crustacean's shell; it supports and protects the soft tissues. In vertebrates the term is sometimes applied to structures produced by the epidermis, such as hair, nails, hoofs, and teeth.

exosmosis
(ek″sos-mo´sis) osmosis or diffusion from within outward.

exostosis
(ek″sos-to´sis) a benign new growth projecting from the surface of a bone. It usually is covered with cartilage. adj., exostot´ic., adj. exostosis cartilaginea a variety of osteoma consisting of a layer of cartilage developing beneath the periosteum of a bone. ...

Exosurf
(ek´so-surf″) trademark for a preparation of synthetic surfactant for treatment of neonatal respiratory distress syndrome.

exothermal
(ek″so-thur´mәl) exothermic.

exothermic
(ek″so-thur´mik) marked or accompanied by the evolution of heat; liberating heat or energy.

exotoxin
(ek´so-tok″sin) a potent toxin formed and excreted by the bacterial cell and found free in the surrounding medium; exotoxins are the most poisonous substances known. They are protein in nature and heat labile, and are detoxified with retention of antigenicity by treatment with formaldehyde. Bacteria of the g...

exotropia
(ek″so-tro´pe-ә) strabismus in which there is permanent deviation of the visual axis of one eye away from that of the other, resulting in diplopia; called also walleye and divergent strabismus. adj., exotro´pic., adj.

expander
(ek-span´dәr) extender. plasma volume expander artificial plasma extender.

expansion
(ek-span´shәn) the process or state of being increased in extent, surface, or bulk. a region or area of increased bulk or surface. dorsal digital expansion , extensor expansion a triangular aponeurotic extension of the digital extensor tendon on the do...

expectancy
(ek-spek´tәn-se) the expected value or probability of occurrence for a specific event. life expectancy the number of years, based on statistical averages, that a given person of a specific age, class, or other demographic variable may be expected to continue living.