conduction


conduction
1. The act of transmitting or conveying certain forms of energy, such as heat, sound, or electricity, from one point to another, without evident movement in the conducting body. 2. The transmission of stimuli of various sorts by living protoplasm. [L. con- duco, pp. ductus, to lead, conduct]
- aberrant ventricular c. abnormal intraventricular c. of a supraventricular beat, especially where surrounding beats are normally conducted. SYN: ventricular aberration.
- accelerated c. any pathologically increased speed of c.; usually occurs between the atrium and ventricles as in the Wolff-Parkinson-White and Lown-Ganong-Levine syndromes; such accelerated pathways provide the bases for particular forms of reentry tachycardia.
- air c. in relation to hearing, the transmission of sound to the inner ear through the external auditory canal and the structures of the middle ear.
- anomalous c. c. of cardiac electrical impulses through any abnormal pathway.
- antegrade c. SYN: anterograde c..
- anterograde c. c. in the expected normal direction between any cardiac structures. SYN: antegrade c., forward c., orthograde c..
- atrioventricular c. (AVC), AV c. forward c. of the cardiac impulse from atria to ventricles via the AV node or any bypass tract, represented in the electrocardiogram by the PR interval. PH c. time is from the onset of the P wave to the first high-frequency component of the His bundle electrogram (normally 119 ± 38 msec); A-H c. time is from the onset of the first high-frequency component of the atrial electrogram to the first high-frequency component of the His bundle electrogram (normally 92 ± 38 msec); P-A c. time is from the onset of the P wave to the onset of the atrial electrogram (normally 27 ± 18 msec).
- avalanche c. the discharge of an impulse from a neuron into a large number of neurons of the same physiologic system, thus producing the liberation of a very large amount of nervous energy by a given stimulus.
- bone c. in relation to hearing, the transmission of sound to the inner ear through vibrations applied to the bones of the skull. SYN: osteophony.
- concealed c. c. of an impulse through a part of the heart without direct evidence of its presence in the electrocardiogram; c. is inferred only because of its influence on the subsequent cardiac cycle.
- decremental c. impaired c. in a portion of a fiber because of progressively lessening response of the unexcited portion of the fiber to the action potential coming toward it; it is manifested by decreasing speed of c., amplitude of action potential, and extent of spread of the impulse.
- delayed c. first-degree AV block. See atrioventricular block, intraventricular block, bundle-branch block.
- forward c. SYN: anterograde c..
- intraatrial c. c. of the cardiac impulse through the atrial myocardium, represented by the P wave in the electrocardiogram.
- intraventricular c. c. of the cardiac impulse through the ventricular myocardium, represented by the QRS complex in the electrocardiogram. HR c. time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the QRS complex of the surface electrocardiogram (normally 43 ± 12 msec); HV c. time is from the onset of the first high-frequency component of the His bundle electrogram to the onset of the ventricular electrogram (normally approximates the HR interval but may be a little shorter). SYN: ventricular c..
- nerve c. the transmission of an impulse along a nerve fiber.
- orthograde c. SYN: anterograde c..
- Purkinje c. c. of the cardiac impulse through the Purkinje system.
- retrograde VA c. c. backward from the ventricles or from the AV node into and through the atria. SYN: retroconduction, ventriculoatrial c., VA c..
- saltatory c. c. in which the nerve impulse jumps from one node of Ranvier to the next.
- sinoventricular c. a rare form of c. of the sinus impulse during paralysis of the atrial muscle by hyperkalemia. The impulse leaves the sinus node and enters the internodal tracts rapidly achieving the junctional tissues but without inscribing a P wave due to the inactivation of the atrial muscle cells.
- supernormal c. SYN: supranormal c..
- supranormal c. transmission of an impulse during the brief period of the cardiac cycle when it would be expected to fail if it occurred outside this time interval; considered to be better than expected rather than better than normal. Cf.:supranormal excitability. SYN: supernormal c..
- synaptic c. the c. of a nerve impulse across a synapse.
- ventriculoatrial c. (VAC), VA c. SYN: retrograde VA c..

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con·duc·tion kən-'dək-shən n
1 a) transmission through or by means of a conductor also the transfer of heat through matter by communication of kinetic energy from particle to particle with no net displacement of the particles
b) CONDUCTIVITY
2) the transmission of excitation through living tissue and esp. nervous tissue <\conduction of impulses to the brain>

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con·duc·tion (kən-dukґshən) the transfer of sound waves, heat, nervous impulses, or electricity; see also under system.

Medical dictionary. 2011.

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  • conduction — [ kɔ̃dyksjɔ̃ ] n. f. • XIIIe; lat. conductio, rac. conducere « conduire; 2. louer » 1 ♦ Dr. rom. Action de prendre qqch. en location. ⇒ location. 2 ♦ (1830) Phys. Conduction électrique : déplacement des charges électriques qui se traduit par un… …   Encyclopédie Universelle

  • Conduction — Con*duc tion (k[o^]n*d[u^]k sh[u^]n), n. [L. conductio a bringing together: cf. F. conduction.] 1. The act of leading or guiding. Sir W. Raleigh. [1913 Webster] 2. The act of training up. [Obs.] B. Jonson. [1913 Webster] 3. (Physics) Transmission …   The Collaborative International Dictionary of English

  • conduction — 1530s, hiring; 1540s, leading, guidance, from O.Fr. conduction hire, renting, from L. conductionem (nom. conductio), noun of action from pp. stem of conducere (see CONDUCE (Cf. conduce)). Sense of conducting of a liquid through a channel is from… …   Etymology dictionary

  • conduction — CONDUCTION. s. f. L action de prendre à loyer. Il n est d usage qu au Palais …   Dictionnaire de l'Académie Française 1798

  • conduction — ► NOUN ▪ the transmission of heat or electricity directly through a substance, without motion of the material. DERIVATIVES conductive adjective …   English terms dictionary

  • conduction — [kən duk′shən] n. [L conductio: see CONDUCT] 1. a conveying, as of liquid through a channel, esp. in plants 2. Physics a) transmission of electricity, heat, etc. through a material b) CONDUCTIVITY: see also CONVECTION, RADIATION …   English World dictionary

  • conduction — Synonyms and related words: communication, conductance, conductivity, conductor, contagion, convection, delivery, deportation, diapedesis, dielectric, diffusion, dissemination, electric conduction, export, exportation, expulsion, extradition, gas …   Moby Thesaurus

  • Conduction — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Physique Conduction thermique : est le mode de transfert de chaleur provoqué par une différence de température entre deux régions d un même milieu ou …   Wikipédia en Français

  • conduction — elektrinis laidumas statusas T sritis chemija apibrėžtis Medžiagos savybė praleisti elektros srovę veikiant išoriniam elektriniam laukui. atitikmenys: angl. conduction; electric conduction; electrical conduction rus. электропроводность …   Chemijos terminų aiškinamasis žodynas

  • conduction — [[t]kəndʌ̱kʃ(ə)n[/t]] N UNCOUNT: usu with supp Conduction is the process by which heat or electricity passes through or along something. [TECHNICAL] Temperature becomes uniform by heat conduction until finally a permanent state is reached …   English dictionary

  • conduction — laidumas statusas T sritis automatika atitikmenys: angl. conduction; conductivity vok. Leitfähigkeit, f; Leitung, f; Leitvermögen, n rus. проводимость, f pranc. conductibilité, f; conduction, f …   Automatikos terminų žodynas


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