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Medical Dictionary - Dictionary of Medicine and Human Biology


Medical Dictionary


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reserpine (re-ser′pen, -pin)
An ester alkaloid isolated from the root of certain species of Rauwolfia; it decreases the 5-hydroxytryptamine and catecholamine concentrations in the central nervous system and in peripheral tissues; used in conjunction with other hypotensive agents in the management of essential hypertension and useful as a tranquilizer in psychotic states.

reserve (re-zerv′)
Something available but held back for later use, as strength or carbohydrates. [L. re-servo, to keep back, r.] alkali r. the sum total of the basic ions (mainly bicarbonates) of the blood and other body fluids that, acting as buffers, maintain the normal pH of the blood. breathing r. the difference between the pulmonary ventilation ( i.e., the volume of air breathed under ordinary resting conditions) and the maximum breathing capacity. cardiac r. the work that the heart is able to perform beyond that required under the ordinary circumstances of daily life, depending upon the state of the myocardium and the degree to which, within physiologic limits, the cardiac muscle fibers can be stretched by the volume of blood reaching the heart during diastole.

reservoir (rez′ev-wor)
SYN: receptaculum. [Fr.] r. of infection living or nonliving material in or on which an infectious agent multiplies and/or develops and is dependent for its survival in nature. Ommaya r. a plastic container placed in the subgaleal space that is connected to the lateral ventricle or tumor cyst by tubing; it is used to instill medication into, or remove fluid from, the ventricle or tumor cyst. Pecquet r. SYN: cisterna chyli. r. of spermatozoa the site where spermatozoa are stored; the distal portion of the tail of the epididymis and the beginning of the ductus deferens. vitelline r. SYN: vitellarium.

reset nodus sinuatrialis (re′set no′dus si′noo-a-tre-a′lis)
Reset of the sinoatrial node produced by premature depolarization (usually atrial) when the sum of the duration of the premature cycle and the return cycle is less than twice the spontaneous cycle length. Cf.:nonreset nodus sinuatrialis. SYN: sinus node reset.

resident (rez′i-dent)
A house officer attached to a hospital for clinical training; formerly, one who actually resided in the hospital. SYN: r. physician. [L. resideo, to reside]

residua (re-zid′u-a)
Plural of residuum.

residual (re-zid′u-al)
Relating to or of the nature of a residue.

residue (rez′i-doo)
That which remains after removal of one or more substances. SYN: residuum. [L. residuum] day r. psychoanalytic term for a dream related to an experience of the previous day.

residuum, pl .residua (re-zid′u-um, -u-a)
SYN: residue. [L. ntr. of residuus, left behind, remaining, fr. re- sideo, to sit back, remain behind]

resilience (re-zil′yens)
1. Energy (per unit of volume) released upon unloading. 2. Springiness or elasticity. [L. resilio, to spring back, rebound]

resin (rez′in, roz′in)
1. An amorphous brittle substance consisting of the hardened secretion of a number of plants, probably derived from a volatile oil and similar to a stearoptene. 2. SYN: rosin. 3. A precipitate formed by the addition of water to certain tinctures. 4. A broad term used to indicate organic substances insoluble in water; these monomers are named according to their chemical composition, physical structure, and means for activation or curing, e.g., acrylic r., autopolymer r.. [L. resina] acrylic r. a general term applied to a resinous material of the various esters of acrylic acid; used as a denture base material, for other dental restorations, and for trays. activated r. SYN: autopolymer r.. anion-exchange r. See anion exchange, anion exchanger. autopolymer r., autopolymerizing r. any r. that can be polymerized by chemical catalysis rather than by the application of heat or light; used in dentistry for dental restoration, denture repair, and impression trays. SYN: activated r., cold cure r., cold-curing r., quick cure r., self-curing r.. carbacrylamine resins a mixture of the cation-exchange resins, carbacrylic r. and potassium carbacrylic r. (87.5%), and of the anion-exchange r., polyamine-methylene r. (12.5%), used to increase the fecal excretion of sodium in edema associated with excessive sodium retention by the kidneys, e.g., in congestive heart failure, cirrhosis of the liver, and nephrosis. cation-exchange r. See cation exchange, cation exchanger. chemically cured r. a r. that contains an initiator, usually benzoyl peroxide, and an activator, usually a tertiary amine, in separate pastes. When mixed, the amine reacts with the benzoyl peroxide to form free radicals and polymerization occurs. cholestyramine r. a strongly basic anion-exchange r. in the chloride form, consisting of a copolymer of styrene and divinylbenzene with quaternary ammonium functional groups; it lowers the blood cholesterol by binding the bile acids in the intestine, thus promoting their excretion in the feces instead of reabsorption from the bowel; used in the treatment of hypercholesterolemia, xanthomatous biliary cirrhosis, and other forms of xanthomatosis; also will bind numerous drugs in the intestine, reducing their bioavailability. cold cure r., cold-curing r. SYN: autopolymer r.. composite r. a synthetic r. usually acrylic based, to which a glass or natural silica filter has been added. Used mainly in dental restorative procedures. [L. compositus, put together, fr. compono, to put together] copolymer r. synthetic r. produced by joint polymerization of two or more different monomers or polymers. cross-linked r. SYN: cross-linked polymer. direct filling r. an autopolymerizing r. especially designed as a dental restorative material. dual-cure r. a r. that utilizes both light and chemical initiation to activate polymerization. epoxy r. any thermosetting r. based on the reactivity of epoxy; used as adhesives, protective coatings, and embedding media for electron microscopy. gum r. the dry exudate from a number of plants, consisting of a mixture of a gum and a r., the former soluble in water but not alcohol, the latter soluble in alcohol but not water. heat-curing r. r. that requires heat to initiate polymerization. Indian podophyllum r. r. obtained from Podophyllum emodi; a cathartic and cholagogue. ion-exchange r. See ion exchange, ion exchanger. ipomea r. r. obtained from the dried root of Ipomoea orizabensis; a cathartic. SEE ALSO: scammony. jalap r. r. extracted from the dried tuberous root of Exogonium purga; a purgative. light-activated r. SYN: light-cured r.. light-cured r. a r. that uses visible or ultraviolet light to excite a photoinitiator, which interacts with an amine to form free radicals and initiate polymerization; used mainly in restorative dentistry. SYN: light-activated r.. melamine r. a plastic material mixed with plaster of Paris for casts. Such a cast is lighter and stronger than one made with plaster of Paris alone. SYN: melamine formaldehyde. methacrylate r. a translucent plastic material, used for the manufacture of various medical appliances, surgical instruments, and seating components used in total joint replacement; it possesses the optical properties of fused quartz and is readily molded when heated; formerly used in electron microscopy for embedding tissues, now superseded by epoxy resins. podophyllum r. a r. extracted from the dried roots and rhizomes of Podophyllum peltatum, a perennial herb common in moist, shady situations in the eastern parts of Canada and the United States. The drug has been used by American Indians as a vermifuge and emetic. The chief constituents of the r. belong to the group of lignins, which are Cl18 compounds related biosynthetically to the flavonoids and derived by dimerization of two C6-C3 units. The most important ones present in podophyllum r. are podophyllotoxin (about 20%), β-peltatin (about 10%), and α-peltatin (about 5%). All three occur both free and as glucosides. The r. has been used as a purgative but has been replaced by milder agents. It is cytotoxic and used as a paint in the treatment of soft venereal and other warts. SYN: May apple root, podophyllin, wild mandrake. polyamine-methylene r. a synthetic acid-binding r. used as a gastric antacid. polyester r. r. in which the polymers are insoluble in most organic solvents and are polymerized by light, heat, or oxygen; used in electron microscopy as a tissue-embedding medium. quick cure r. SYN: autopolymer r.. quinine carbacrylic r. SYN: azuresin. self-curing r. SYN: autopolymer r..

resin acids
A class of organic compounds derived from various natural plant resins; diterpenes containing a phenanthrene ring system; e.g., abietic acid, pimaric acid, ester gums. SYN: resinic acids.

resinates (rez′in-ats)
Salts or esters of resin acids.

resines (rez′ens)
Esters of resin acids.

resinic acids
SYN: resin acids.

resinoid (rez′i-noyd)
1. A substance containing a resin or resembling one. 2. An extract obtained by evaporating a tincture. 3. Resembling rosin.

resinols (rez′in-ols)
Resin alcohols.

resinous (rez′i-nus)
Relating to or derived from a resin.

resistance (re-zis′tans)
1. A force exerted in opposition to an active force. 2. The opposition in a conductor to the passage of a current of electricity, whereby there is a loss of energy and a production of heat; specifically, the potential difference in volts across the conductor per ampere of current flow; unit: ohm. Cf.:impedance (1) . 3. The opposition to flow of a fluid through one or more passageways ( e.g., blood flow, respiratory gases in the tracheobronchial tree), analogous to (2); units are usually those of pressure difference per unit flow. Cf.:impedance (2) . 4. In psychoanalysis, an individual's unconscious defense against bringing repressed thoughts to consciousness. 5. The ability of red blood cells to resist hemolysis and to preserve their shape under varying degrees of osmotic pressure in the blood plasma. 6. The natural or acquired ability of an organism to maintain its immunity to or to resist the effects of an antagonistic agent, e.g., pathogenic microorganism, toxin, drug. [L. re-sisto, to stand back, withstand] airway r. in physiology, the r. to flow of gases during ventilation due to obstruction or turbulent flow in the upper and lower airways; to be differentiated during inhalation from r. to inflation due to decreases in pulmonary or thoracic compliance. bacteriophage r. r. of a bacterial mutant to infection by a bacteriophage to which the parent (wild-type) strain is susceptible. dicumarol r. [MIM*122700] an autosomal dominant disorder characterized by r. to dicumarol, over and above general variability in tolerance to the drug; caused by mutation in the coumarin 7-hydroxylase gene (CYP2A6) on chromosome 19p. drug r. the capacity of disease-causing microorganisms to withstand drugs previously toxic to them; achieved by spontaneous mutation or through selective pressure after exposure to the drug in question. Pathogenic microorganisms resist antibiotics by various mechanisms, including the production of enzymes ( e.g., β-lactamases) that chemically inactivate antibiotic molecules. In mixed infections of the respiratory tract, a β-lactamase (penicillinase) produced by one organism ( e.g., Haemophilus influenzae) can inactivate penicillin and so block its effectiveness against other organisms in the mixture that possess no r. of their own ( e.g., group A β-hemolytic streptococci). Usually an organism that has acquired r. to a given antibiotic is resistant to others in the same chemical class. Some bacteria transmit antibiotic r. to their offspring not chromosomally but via plasmids, which lie outside the bacterial nucleus but perform certain genetic functions. Bacteria of one species can develop r. to certain antibiotics by acquiring plasmids from bacteria of another species.Drug r. is a growing problem worldwide. Many strains of bacteria, fungi, and parasites have developed r., including pneumococci, gonococci, salmonellae, Mycobacterium tuberculosis, Tinea tonsurans, and Plasmodium falciparum. In some parts of the U.S., 40% of pneumococcal isolates and 90% of staphylococci are resistant to penicillin. The prevalence of both vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus has increased 20-fold since 1989. Factors favoring development of antibiotic r. include inappropriate prescribing of antibiotics (e.g., to treat viral infections); indiscriminate use of newly developed, extended-spectrum agents; empiric and broad-spectrum treatment of infections in certain populations (e.g., children, the elderly, and residents of long-term care facilities); prescribing of sublethal doses; and failure of patients to complete courses of antibiotic treatment. The Centers for Disease Control and Prevention estimates that U.S. physicians write 50 million unnecessary antibiotic prescriptions annually, including 17 million to treat the common cold. Infectious disease experts and public health authorities have called for restraint by primary care physicians in prescribing antibiotics, particularly for children and for uncomplicated upper respiratory infections, acute bronchitis (nearly always viral), and acute sinusitis and otitis media (in neither of which have reliable diagnostic criteria for bacterial infection been established). They have also stressed the importance of public education, since inappropriate expectations of patients or their parents have been a driving factor in antibiotic overuse by physicians. Administration of antibiotics to livestock animals, chiefly for disease prophylaxis and growth promotion, has also contributed to the emergence of resistant strains of bacteria. expiratory r. r. to flow of gas out of the lungs or the total r. to flow of gas during the expiratory phase of the respiratory cycle. impact r. the ability of a lens for eyewear to withstand impact without shattering or breaking, i.e., of a 38-inch steel ball dropped 50 ft; criteria for determination of impact r. are specified by U.S. regulations. inductive r. SYN: reactance. insulin r. diminished effectiveness of insulin in lowering plasma glucose levels, arbitrarily defined as a daily requirement of at least 200 units of insulin to prevent hyperglycemia or ketosis; usually due to binding of insulin or insulin receptor sites by antibodies; associated with obesity, ketoacidosis, and infection.Impairment of the normal response of muscle and other cells to endogenous or exogenous insulin often complicates the deficiency of endogenous insulin that is characteristic of type 2 diabetes mellitus. It is a peripheral phenomenon and can occur even when the quality and quantity of insulin produced by the pancreas are normal. It apparently results from a decrease in the number of insulin receptor sites on cells, a malfunction of the biochemical glucose transport system, or both. Insulin r. is often associated with high levels of circulating antibody to insulin receptors. The phenomenon of insulin r. explains why some people with type 2 diabetes have hyperinsulinemia in the fasting state, often coexisting with elevated plasma glucose levels. Insulin r. correlates closely with obesity in diabetes. It occurs less frequently in lean diabetics, whose principal problem is usually primary failure of insulin production. Insulin r. is often seen in persons with or without frank diabetes who have other endocrine or systemic disorders, including dyslipidemias, hypertension, hyperuricemia, and chronic infection. Some women with polycystic ovaries, hirsutism, and anovulation also have insulin r. and hyperinsulinemia. Troglitazone, a newer agent used in the treatment of type 2 diabetes mellitus, improves insulin sensitivity. multidrug r. the insensitivity of various tumors to a variety of chemically related anticancer drugs; mediated by a process of inactivating the drug or removing it from the target tumor cells. mutual r. SYN: antagonism. peripheral r. SYN: total peripheral r.. synaptic r. the ease or difficulty with which a nerve impulse can cross a synapse. systemic vascular r. an index of arteriolar compliance or constriction throughout the body; proportional to the blood pressure divided by the cardiac output. thyrotropin r. an autosomal recessive disorder in which the thyrocytes are unresponsive to thyrotropin. Cf.:pseudohypoparathyroidism. total peripheral r. (TPR) the total r. to flow of blood in the systemic circuit; the quotient produced by dividing the mean arterial pressure by the cardiac minute-volume. SYN: peripheral r..

resistivity (re′zis-tiv′i-te)
A measure of a material's resistance to the passage of electrical current; the reciprocal of conductivity. [L. re-sito, to withstand]

resistor (re-zis′ter, -tor)
An element included in an electric circuit to provide resistance to the flow of current.

resolution (rez-o-loo′shun)
1. The arrest of an inflammatory process without suppuration; the absorption or breaking down and removal of the products of inflammation or of a new growth. See line pairs, under pair. 2. The optical ability to distinguish detail such as the separation of closely adjacent objects. SYN: resolving power (3) . [L. resolutio, a slackening, fr. re-solvo, pp. -solutus, to loosen, relax]

resolvase (re-sol′vaz)
A gene encoded by a transposon that can catalyze a second stage of transposition as well as participate in the regulation of its own expression. [resolve + -ase]

resolve (re-zolv′)
To return or cause to return to the normal, particularly without suppuration, said of a phlegmon or other form of inflammation. [L. resolvo, to loosen]

resolvent (re-zol′vent)
1. Causing resolution. 2. An agent that arrests an inflammatory process or causes the absorption of a neoplasm.

resonance (rez′o-nans)
1. Sympathetic or forced vibration of air in the cavities above, below, in front of, or behind a source of sound; in speech, modification of the quality ( e.g., harmonics) of a tone by the passage of air through the chambers of the nose, pharynx, and head, without increasing the intensity of the sound. 2. The sound obtained on percussing a part that can vibrate freely. 3. The intensification and hollow character of the voice sound obtained on auscultating over a cavity. 4. In chemistry, the manner in which electrons or electric charges are distributed among the atoms in compounds that are planar and symmetric, particularly those with conjugated (alternating) double bonds; the existence of r. in the latter case lowers the energy content and increases the stability of a compound. 5. The natural or inherent frequency of any oscillating system. 6. SYN: resonant frequency. [L. resonantia, echo, fr. re-sono, to resound, to echo] amphoric r. a percussion sound, like that produced by striking a large empty bottle, obtained by percussing over a pulmonary cavity. SYN: cavernous r.. bandbox r. SYN: vesiculotympanitic r.. bellmetal r. in cases of a large pulmonary cavity or of pneumothorax, a clear metallic sound obtained by striking a coin, held against the chest, by another coin, or by flicking the chest wall with one's fingernail; the sound is heard on auscultating the chest wall on the same side anteroposteriorly. SYN: anvil sound, bell sound, coin test. cavernous r. SYN: amphoric r.. cracked-pot r. a peculiar sound, resembling that heard on striking a cracked pot, elicited on percussing over a pulmonary cavity that communicates with a bronchial tube, when the patient's mouth is open. SYN: cracked-pot sound. electron paramagnetic r. (EPR) SYN: electron spin r.. electron spin r. (ESR) a spectrometric method, based on measurement of electron spins and magnetic moments, for detecting and estimating free radicals in reactions and in biologic systems. SYN: electron paramagnetic r.. hydatid r. a peculiar vibratile r. heard on auscultatory percussion over a hydatid cyst. nuclear magnetic r. (NMR) the phenomenon in which certain atomic nuclei possessing a magnetic moment will precess around the axis of a strong external magnetic field, the frequency of precession (Larmor frequency) being specific for each nucleus and the strength of the magnetic field; spinning nuclei induce their own oscillating magnetic fields and therefore emit electromagnetic radiation that can produce a detectable signal at the Larmor frequency. NMR is used as a method of identifying covalent bonds and is applied clinically in magnetic r. imaging. skodaic r. a peculiar, high-pitched sound, less musical than that obtained over a cavity, elicited by percussion just above the level of a pleuritic effusion. SYN: Skoda sign, Skoda tympany. tympanitic r. SYN: tympany. vesicular r. the sound obtained on percussing over the normal lungs. vesiculotympanitic r. a peculiar, partly tympanitic, partly vesicular sound, obtained on percussion in cases of pulmonary emphysema. SYN: bandbox r., wooden r.. vocal r. (VR) the voice sounds as heard on auscultation of the chest. wooden r. SYN: vesiculotympanitic r..

resonator (rez′o-na-ter)
A device for employing inductance to create an electric current of very high potential and small volume.

resorb (re-sorb′)
To reabsorb; to absorb what has been excreted, as an exudate or pus. [L. re-sorbeo, to suck back]

resorcin (re-zor′sin)
SYN: resorcinol.

resorcinol (re-zor′si-nol)
An external antiseptic in psoriasis, eczema, seborrhea, and ringworm; pyrocatechol and hydroquinone are isomers of r.. SYN: resorcin. r. monoacetate used externally in the treatment of acne, sycosis, and seborrhea. r. phthalic anhydride SYN: fluorescein.

resorcinolphthalein (re-zor′si-nol-thal′e-in)
SYN: fluorescein. r. sodium SYN: fluorescein sodium.

resorption (re-sorp′shun)
1. The act of resorbing. 2. A loss of substance by lysis, or by physiologic or pathologic means. bone r. the removal of osseous tissue. gingival r. SYN: gingival recession. horizontal r. SYN: horizontal atrophy. internal r. a loss of tooth structure originating within the pulp cavity. ridge r. a loss in the volume and size of the alveolar portion of the mandible or maxilla. root r. dissolution of the root of a tooth; either external, with loss or blunting of the apical portion, or internal, with loss of dentin from the inside (pulpal) part of the root area.

respirable (re-spir′a-bl, res′pi-ra-bl)
Capable of being breathed.

respiration (res-pi-ra′shun)
1. A fundamental process of life, characteristic of both plants and animals, in which oxygen is used to oxidize organic fuel molecules, providing a source of energy as well as carbon dioxide and water. In green plants, photosynthesis is not considered r. 2. SYN: ventilation (2) . [L. respiratio, fr. respiro, pp. -atus, to exhale, breathe] abdominal r. breathing effected mainly by the action of the diaphragm. aerobic r. a form of r. in which molecular oxygen is consumed and carbon dioxide and water are produced. amphoric r. a sound like that made by blowing across the mouth of a bottle, heard on auscultation in some cases in which a large pulmonary cavity exists, or occasionally in pneumothorax. anaerobic r. a form of r. in which molecular oxygen is not consumed; e.g., nitrate r., sulfate r.. artificial r. SYN: artificial ventilation. assisted r. SYN: assisted ventilation. Biot r. completely irregular breathing pattern, with continually variable rate and depth of breathing; results from lesions in the respiratory centers in the brainstem, extending from the dorsomedial medulla caudally to the obex. SYN: ataxic breathing, Biot breathing, respiratory ataxia. bronchial r. a tubular blowing sound caused by the passage of air through a bronchus in an area of consolidated lung tissue. bronchovesicular r. combined bronchial and vesicular r.. cavernous r. a hollow reverberating sound heard on auscultation over a cavity in the lung. Cheyne-Stokes r. the pattern of breathing with gradual increase in depth and sometimes in rate to a maximum, followed by a decrease resulting in apnea; the cycles ordinarily are 30 seconds to 2 minutes in duration, with 5–30 seconds of apnea; seen with bilateral deep cerebral hemispheric lesions, with metabolic encephalopathy, and, characteristically, in coma from affection of the nervous centers of r.. cogwheel r. the inspiratory sound interrupted by one or two by silent intervals. SYN: interrupted r., jerky r.. controlled r. SYN: controlled ventilation. costal r. SYN: thoracic r.. diffusion r. maintenance of oxygenation during apnea by intratracheal insufflation of oxygen at high flow rates. SYN: apneic oxygenation. electrophrenic r. the rhythmic electric stimulation of the phrenic nerve by an electrode applied to the skin at the motor points of the phrenic nerve; it is used in paralysis of the respiratory center resulting from acute bulbar poliomyelitis. external r. the exchange of respiratory gases in the lungs as distinguished from internal or tissue r.. forced r. voluntary hyperventilation. internal r. SYN: tissue r.. interrupted r. SYN: cogwheel r.. jerky r. SYN: cogwheel r.. Kussmaul r. deep, rapid r. characteristic of diabetic or other causes of acidosis. SYN: Kussmaul-Kien r.. Kussmaul-Kien r. SYN: Kussmaul r.. labored r. difficult, usually deep, breathing in patients with cardiac or pulmonary disease or disease affecting nervous system control of ventilation. mouth-to-mouth r. a method of artificial ventilation involving an overlap of the patient's mouth (and nose in small children) with the operator's mouth to inflate the patient's lungs by blowing, followed by an unassisted expiratory phase brought about by elastic recoil of the patient's chest and lungs; repeated 12–16 times a minute; where the nose is not covered by the operator's mouth, the nostrils must be closed by pinching. nitrate r. the process of r. used by some anaerobic organisms, in which nitrate rather than molecular oxygen is used to oxidize organic molecules to obtain energy. paradoxical r. deflation of the lung during inspiration and inflation of the lung during the phase of expiration; seen in the lung on the side of an open pneumothorax. puerile r. an exaggeration of the normal respiratory sounds, heard in children and in adults after exertion. stertorous r. harsh, noisy breathing usually heard in a comatous patient. SYN: stertorous breathing. sulfate r. the process of r. used by some anaerobic organisms, in which sulfate rather than molecular oxygen is used to oxidize organic molecules to obtain energy. thoracic r. r. effected chiefly by the action of the intercostal and other muscles that raise the ribs, causing expansion of the chest. SYN: costal r.. tissue r. the interchange of gases between the blood and the tissues. SYN: internal r.. tubular r. high-pitched bronchial r.. vesicular r. the respiratory murmur heard on auscultating over the normal lung. SYN: respiratory murmur, vesicular murmur. vesiculocavernous r. cavernous r., due to the presence of a cavity, mingled with the vesicular murmur of the surrounding normal lung tissue.

respirator (res′pi-ra-ter, -tor)
1. An apparatus for administering artificial respiration in cases of respiratory failure. 2. An appliance fitting over the mouth and nose, used for the purpose of excluding dust, smoke, or other irritants, or of otherwise altering the air before it enters the respiratory passages. SYN: inhaler (1) . SYN: ventilator. cuirass r. one of several types of respirators producing alternating negative pressure about the thoracic cage; now rarely used. Drinker r. a mechanical r. in which the body (except the head) is encased within a metal tank, which is sealed at the neck with an airtight gasket; artificial respiration is induced by making the air pressure inside negative. SYN: iron lung, tank r.. pressure-controlled r. a r. that provides a predetermined pressure to gases during inhalation, the volume of gas moved being variable, depending upon resistance. tank r. SYN: Drinker r.. volume-controlled r. a r. that provides a predetermined volume of gases during inhalation, with the pressure required to move that volume remaining variable, depending upon resistance.

respiratory (res′pi-ra-tor-e, re-spir′a-tor-e)
Relating to respiration.

respire (re-spir′)
1. To breathe. 2. To consume oxygen and produce carbon dioxide by metabolism. [L. respiro, to breathe]

respirometer (res-pi-rom′e-ter)
1. An instrument for measuring the extent of the respiratory movements. 2. An instrument for measuring oxygen consumption or carbon dioxide production, usually of an isolated tissue. [L. respiro, to breathe, + G. metron, measure] Dräger r. an inferential meter to measure tidal and minute volume from the number of revolutions of a vane rotated by the gas stream as the latter passes through two lightweight lozenge-shaped meshing rotors. Wright r. an inferential meter to measure tidal and minute volume from the number of revolutions of a vane rotated by the gas stream as the latter passes through 10 tangential slots in a cylindric stator ring to turn a flat two-bladed rotor; also called Wright spirometer.

response (re-spons′)
1. The reaction of a muscle, nerve, gland, or other excitable tissue to a stimulus. 2. Any act or behavior, or its constituents, that a living organism is capable of emitting. Reflexes are usually excluded because they are typically elicited by a specifiable (unconditioned or natural) stimulus rather than emitted under circumstances in which the stimulus was not specifiable. [L. responsus, an answer] acute phase r. SYN: acute phase reaction. anamnestic r. (an′am-nes-tik) SYN: secondary immune r.. See immune r.. auditory brainstem r. (ABR) an electrophysiologic measure of auditory function utilizing computer-averaged responses produced by the auditory nerve and the central auditory pathways principally in the brainstem to repetitive acoustic stimuli. ABR is also used to locate the lesion and determine the type of hearing impairment (sensory versus neural). SYN: brainstem evoked r.. automatic auditory brainstem r. a technique of ABR in which the stimulus modification is programmed on the basis of the electrical responses recorded. The device determines automatically if predetermined thresholds have been achieved. It is useful in newborn hearing screening. biphasic r. 1. two separate and distinct responses that are separated in time; 2. immediate reaction to an antigenic challenge followed by a recurrence of symptoms after an interval of quiescence. blink r. a r. elicited during nerve conduction studies, consisting of muscle action potentials evoked from orbicularis oculi muscles after brief electric or mechanical stimuli to the cutaneous area supplied by the ophthalmic branch of the trigeminal nerve. Characteristically, there is an early r. (approximately 10 ms after stimulus) ipsilateral to the stimulation site (labeled R1) and bilateral late responses (approximately 30 ms after stimulus; labeled R2); the latter are responsible for the visible twitch of the orbicularis oculi muscles. booster r. SYN: secondary immune r.. See immune r.. brainstem evoked r. (BSER) SYN: auditory brainstem r.. conditioned r. a r. already in an individual's repertoire but which, through repeated pairings with its natural stimulus, has been acquired or conditioned anew to a previously neutral or conditioned stimulus. See conditioning. Cf.:unconditioned r.. Cushing r. SYN: Cushing phenomenon. depletion r. subnormal metabolic r. to trauma in a person whose physiologic processes are already depressed by disease. early-phase r. prompt onset of symptoms following an antigenic stimulus. evoked r. an alteration in the electrical activity of a region of the nervous system through which an incoming sensory stimulus is passing; may be somatosensory (SER), brainstem auditory (BAER), or visual (VER). SEE ALSO: evoked potential. flight or fight r. emergency theory. galvanic skin r. (GSR) a measure of changes in emotional arousal recorded by attaching electrodes to any part of the skin and recording changes in moment-to-moment perspiration and related autonomic nervous system activity. SYN: galvanic skin reaction, galvanic skin reflex, psychogalvanic reaction, psychogalvanic skin reaction, psychogalvanic reflex, psychogalvanic skin reflex, psychogalvanic r., psychogalvanic skin r.. Henry-Gauer r. inhibition of antidiuretic hormone secretion due to a rise in atrial pressure that stimulates atrial stretch receptors. immune r. 1. any r. of the immune system to an antigen including antibody production and/or cell-mediated immunity; 2. the r. of the immune system to an antigen (immunogen) that leads to the condition of induced sensitivity; the immune r. to the initial antigenic exposure (primary immune r.) is detectable, as a rule, only after a lag period of from several days to 2 weeks; the immune r. to a subsequent stimulus (secondary immune r.) by the same antigen is more rapid than in the case of the primary immune r.. isomorphic r. a r. to trauma at sites of injury in previously uninvolved areas of patients with skin diseases such as psoriasis and lichen planus, typically with linear lesions at sites of scratching or a scar. SYN: Köbner phenomenon. late auditory-evoked r. r. of the auditory cortex to acoustic stimulation. late-phase r. recurrence of symptoms after an appreciable interval following challenge with an antigen; preceded by an initial early-phase r.. level-dependent frequency r. one of several strategies used in hearing aids to alter the balance in amplification between high- and low-frequency sounds. middle latency r. a r. to acoustic stimulation recorded from the auditory cortex of the brain. myotonic r. failure of muscle relaxation caused by repetitive discharge of muscle fiber action potentials. oculomotor r. widespread myogenic potential evoked by visual stimuli. orienting r. SYN: orienting reflex. postural sway r. the body sway induced by vestibular stimulation. primary immune r. immune r.. psychogalvanic r. (PGR) , psychogalvanic skin r. SYN: galvanic skin r.. recruiting r. SYN: recruitment (2) . relaxation r. an integrated hypothalamic reaction resulting in decreased sympathetic nervous system activity which, physiologically and psychologically, is almost a mirror image of the body's responses to Cannon emergency theory (flight or fight r.); can be self-induced through the use of techniques associated with transcendental meditation, yoga, and biofeedback. SEE ALSO: emergency theory. secondary immune r. SYN: anamnestic r., booster r..immune r.. sonomotor r. widespread myogenic potential evoked by click stimulation. stringent r. the cellular r. to amino acid starvation that reduces the amount of ribosomes to what can be employed under the nutrient conditions. target r. SYN: operant. triple r. the triphasic r. to the firm stroking of the skin. Phase 1 is the sharply demarcated erythema that follows a momentary blanching of the skin and is the result of release of histamine from the mast cells. Phase 2 is the intense red flare extending beyond the margins of the line of pressure but in the same configuration, and is the result of arteriolar dilation; also called axon flare because it is mediated by axon reflex. Phase 3 is the appearance of a line wheal in the configuration of the original stroking. unconditioned r. a r., such as salivation, which is a part of the animal or human repertoire. Cf.:conditioned r..

rest
1. Quiet; repose. [A.S. raest] 2. To repose; to cease from work. [A.S. raestan] 3. A group of cells or a portion of fetal tissue that has become displaced and lies embedded in tissue of another character. [L. restare, to remain] 4. In dentistry, an extension from a prosthesis that affords vertical support for a restoration. adrenal r. SYN: accessory adrenal. bed r. maintenance of the recumbent position, in bed, to minimize activity and help recovery from disease; formerly used extensively in treatment of tuberculosis, myocardial infarction, and other diseases. cingulum r. the rigid part of a removable partial denture supported by a prepared r. area on the cingulum of an anterior tooth or crown. incisal r. the portion of a removable partial denture supported by an incisal edge. lingual r. a metallic extension onto the lingual surface of a tooth to provide support or indirect retention for a removable partial denture. Malassez epithelial rests epithelial remains of Hertwig root sheath in the periodontal ligament. Marchand r. SYN: Marchand adrenals, under adrenal. mesonephric r. SYN: wolffian r.. occlusal r. a rigid extension of a removable partial denture onto the occlusal surface of a posterior tooth for support of the prosthesis. precision r. a r. consisting of closely interlocking parts. rests of Serres remnants of dental lamina epithelium entrapped within the gingiva. Walthard cell r. a nest of epithelial cells occurring in the peritoneum of the uterine tubes or ovary; when neoplastic, possibly comprising one of the components of the Brenner tumor. wolffian r. remnants of the wolffian duct in the female genital tract that give rise to cysts; e.g., Gartner cyst. SYN: mesonephric r..

restenosis (re′sten-o-sis)
Recurrence of stenosis after corrective surgery on the heart valve; narrowing of a structure (usually a coronary artery) following the removal or reduction of a previous narrowing. [re-, + G. stenosis, a narrowing]

restiform (res′ti-form)
Ropelike; rope-shaped; referring to the r. body, the larger (lateral) part of the inferior cerebellar peduncle; contains fibers from the spinal cord (spinocerebellar) and medulla (cuneo-, olivo-, reticulocerebellar, etc.) to cerebellum. [L. restis, rope, + forma, form]

restitope (res′ti-top)
The part of the T cell receptor that associates with the class II major histocompatibility molecule. [restriction + -tope]

restitution (res-ti-too′shun)
In obstetrics, the return of the rotated head of the fetus to its natural relation with the shoulders after its emergence from the vulva. [L. restitutio, act of restoring]

restoration (res-to-ra′shun)
In dentistry: 1. A prosthetic r. or appliance; a broad term applied to any inlay, crown, bridge, partial denture, or complete denture that restores or replaces lost tooth structure, teeth, or oral tissues. 2. A plug or stopping; any substance such as gold, amalgam, etc., used for restoring the portion missing from a tooth as a result of removing decay in the tooth. [L. restauro, pp. -atus, to restore, to repair] acid-etched r. the r. of tooth structure with a resin after the surface of the tooth has been treated with an acid solution that etches the tooth surface, thereby increasing retention of the r.. combination r. a tooth r. of two or more materials applied in layers. compound r. a r. of more than one surface of a tooth. direct acrylic r. a direct resin r. of autopolymerizing acrylic. direct composite resin r. SYN: direct resin r.. direct resin r. a direct r. made by inserting a plastic mix of auto- or light-polymerized resins in a cavity prepared in a tooth. SYN: direct composite resin r.. overhanging r. a r. with excessive material at the junction of the r. margin and the tooth. permanent r. a definitive r., in contradistinction to a temporary or provisional r.. provisional r. SYN: temporary r.. root canal r. a gutta-percha, silver, or plastic cone that has been carried into a root canal, either alone or in conjunction with a cement, paste, or solvent, for the purpose of obturating the canal space. silicate r. r. of lost tooth structure made with silicate cement. temporary r. a r. to be used for a limited period of time, in contradistinction to a permanent r.. SYN: provisional r..

restorative (re-stor′a-tiv)
1. Renewing health and strength. 2. An agent that promotes a renewal of health or strength. [L. restauro, to restore]




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