| electrical coupling | <physiology> General term for an intimate cytoplasmic contact, mediated by gap junctions, between touching cells, such that electrical current injected into either cell changes the membrane potential of both. In neurons, arrays of gap junctions form electrical synapses, that allow action potentials to pass directly between cells. However, electrical coupling is not confined to excitable cells: many embryonic and adult epithelia are coupled, possibly to allow metabolic cooperation. (18 Nov 1997) |
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| electrical failure | Failure in which the cardiac inadequacy is secondary to disturbance of the electrical impulse. (05 Mar 2000) |
| electrical formula | A graphic representation by means of symbols of the reaction of a muscle to an electrical stimulus. (05 Mar 2000) |
| electrical heart position | A description of the heart's assumed electrical habitus based upon the form of the QRS complexes in leads aVL, aVF, V1, and V6. Sometimes loosely (and inaccurately) used to describe the frontal plane electric axis. Synonym: heart position. (05 Mar 2000) |
| electrical synapse | <physiology> A connection between two electrically excitable cells, such as neurons or muscle cells, via arrays of gap junctions. This allows the cells to be electrically coupled and so an action potential in one cell moves directly into the other, without the 1 ms delay inherent in chemical synapses. Electrical synapses do not allow modulation of their connection and so only occur in neuronal circuits where speed of conduction is paramount (e.g. The crayfish escape reflex). A few electrical synapses are rectifying, implying a more specialised property than a simple gap junction. (18 Nov 1997) |
| electrical systole | The duration of the QRS-T complex (i.e., from the earliest Q-wave to the end of the latest T wave on the ECG). Electromechanical systole, the period from the beginning of the QRS complex to the first (aortic) vibration of the second heart sound. Synonym: Q-S2 interval. (05 Mar 2000) |