| demarcation current | The current set up when an injured part of a nerve, muscle, or other excitable tissue is connected through a conductor with the uninjured region; the injured tissue is negative to the uninjured. Synonym: demarcation current. (05 Mar 2000) |
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| demarcation | A setting of limits; a boundary. Origin: Fr. Fr. L. De, from, + Mediev. L. Marco, to mark (05 Mar 2000) |
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| demarcation line of retina | Junction of avascular and vascular retina in retinopathy of prematurity; line marking the limits of an old retinal detachment. (05 Mar 2000) |
| demarcation potential | The difference in potential recorded when one electrode is placed on intact nerve fibres or muscle fibres and the other electrode is placed on the injured ends of the same fibres; the intact portion is positive with reference to the injured portion. Synonym: injury potential. (05 Mar 2000) |
| line of demarcation | A zone of inflammatory reaction separating a gangrenous area from healthy tissue. (05 Mar 2000) |
| action current | An electrical current induced in muscle fibres when they are effectively stimulated; normally it is followed by contraction. (05 Mar 2000) |
| alternating current | Electrical current which alternates direction periodically. (For instance, household electric current is AC alternating at 60 oscillations/sec (60 Hertz) in the United States, and 50 Hertz in many other countries.) Acronym: AC (09 Oct 1997) |
| anodal current | A current produced in tissues under the anode when the circuit is closed. (05 Mar 2000) |
| ascending current | The direction of current flow in a nerve when the anode is placed peripheral to the cathode, in contrast to descending current; the convention used is that current flows from positive to negative. Synonym: centripetal current. (05 Mar 2000) |
| axial current | The central rapidly moving portion of the bloodstream in an artery. (05 Mar 2000) |
| bootstrap current | <radiobiology> Currents driven in toroidal devices by neo-classical diffusion. They may amount to a substantial fraction of the net current in a tokamak reactor, thus lengthening the pulse time or decreasing the power needed for current drive. (09 Oct 1997) |
| calcium current | Inflow of calcium ions through specific calcium channels. Critically important in release of transmitter substance from presynaptic terminals. (18 Nov 1997) |
| galvanic current | See: direct current, galvanism. (05 Mar 2000) |
| radio frequency current drive | <radiobiology> Plasma waves in the radio-frequency range can be used to push plasma particles in such a way that current forms in the plasma, this is a method of non-inductive current drive which would allow for steady-state fusion reactors to operate. (09 Oct 1997) |
| gating current | <physiology> Small currents in the membrane just prior to the increase in ionic permeability, due to the movement of charged particles within the membrane. So called because they open the gates for current flow through ion channels. (20 Mar 1998) |
| M current | <physiology> Flow of potassium ions through M channels. (26 Mar 1998) |