conduction

conduction /con·duc·tion/ (-shun) conveyance of energy, as of heat, sound, or electricity.conduc´tive

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aberrant conduction  cardiac conduction through pathways not normally conducting cardiac impulses, particularly through ventricular tissue.

aerotympanal conduction  conduction of sound waves to the ear through the air and the tympanum.

air conduction  conduction of sound waves to the inner ear through the external auditory canal and middle ear.

anterograde conduction  transmission of a cardiac impulse in the normal direction, from the sinus node to the ventricles, particularly forward conduction through the atrioventricular node.

Diagrammatic view of the conducting system of the heart, showing anterograde conduction of the cardiac impulse.

bone conduction  conduction of sound waves to the inner ear through the bones of the skull.

concealed conduction  incomplete penetration of a propagating impulse through the cardiac conducting system such that electrocardiograms reveal no evidence of transmission but the behavior of one or more subsequent impulses is somehow affected.

concealed retrograde conduction  retrograde conduction blocked in the atrioventricular node; it does not produce an extra P wave but leaves the node refractory to the next normal sinus beat.

decremental conduction  delay or failure of propagation of an impulse in the atrioventricular node resulting from progressive decrease in the rate of the rise and amplitude of the action potential as it spreads through the node.

retrograde conduction  transmission of a cardiac impulse backward in the ventricular to atrial direction, particularly conduction from the atrioventricular node into the atria.

saltatory conduction  the passage of a potential from node to node of a nerve fiber, rather than along the membrane.

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con·duc·tion (kn-dkshn)

n.

The transmission or conveying of something through a medium or passage, especially the transmission of electric charge or heat through a conducting medium without perceptible motion of the medium itself.

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conduction

[kənduk′shən]

Etymology: L, conducere, to lead

1 (in physics) a process in which heat is transferred from one substance to another because of a difference in temperature; a process (often electrical) in which energy is transmitted through a conductor.

2 (in physiology) the process by which a nerve impulse is transmitted. conductive, adj.

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conduction,

n the carrying of sound waves, heat, light, nerve impulses, and electricity.

conduction, air,

n the process of transmitting sound waves to the cochlea by way of the outer and middle ear. In normal hearing, practically all sounds are transmitted in this way, except those of the hearer's own voice, which are transmitted partly by bone conduction.

conduction, bone,

n the transmission of sound waves or vibrations to the cochlea by way of the bones of the cranium.

conduction, impulse,

n the conduction of an impulse along the nerve fiber, accompanied by an alteration of the electrical potential of the fiber tissue and an exchange of electrolytes across the nerve fiber membrane.

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conduction, conductive

conveyance of energy, as of heat, sound or electricity.

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accessory tract atrioventricular conduction

permits a sinus impulse from the atria to ventricles to precede that carried by the normal atrioventricular conduction system. Arrhythmia results, the particular electrocardiographic characteristics depending on the pathway(s) involved. See also wolff-parkinson-white syndrome.

aerial conduction, air conduction

conduction of sound waves to the organ of hearing through the air.

conduction anesthesia

local anesthesia produced by the injection of an anesthetic agent close to a nerve in order to prevent transmission of nerve impulses along it.

bone conduction

conduction of sound waves to the inner ear through the bones of the skull.

conduction disorder

abnormalities in the conduction pathways of the heart.

James accessory conduction

see james fibers.

conduction system

the system comprises the sinoatrial and atrioventricular nodes, atrioventricular bundle and Purkinje fibers.

Conduction system of the heart. By permission from Cunningham JG, Textbook of Veterinary Physiology, Saunders, 2002

conduction time

an indicator of a peripheral nerve's ability to carry an impulse; measured during electromyography. A nerve that has undergone Wallerian degeneration is unable to carry an impulse. Severe loss of myelin results in a prolonged conduction time.

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conduction

Cardiac pacing The passage of an electrical charge; the active propagation of a depolarization wave in the heart Physiology The transmission of nerve impulses. See Retrograde conduction.