Laws polar irritation of excitable tissues DC

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Early in the second half of the XIX century by Pfluger were formulated regularities in the action of a direct current in excitable tissue. Basically they boil down to the following. The excitation occurs at the moment of power under the cathode in a off - under the anode, and to excitation under the anode need more current than when snapping under the cathode. This law polar irritation easily demonstrated by a number of experiments.
The muscle in the middle of a tight bandage to the full, loss of conductivity. To the two ends connected with recording devices, put the electrodes from a DC source. When closing the chain is reduced half muscles, connected with the cathode, and open - half, connected to the anode.
On the nerve polar irritation illustrated by the following experience. Nerve tied up so tightly that in this part of the physiological conductivity completely interrupted. On both sides of the bandaged area placed electrodes from a DC source. The muscle is at the closure of the chain, more to drink, is the cathode, and open circuit, if closer to the anode.
However, the effect of direct current is not limited to only short-term effects during circuit and open circuit.
The same author has shown that the current valid for the entire time of passage through the fabric. Under the cathode anxiety rises and keeps all the time. After turning off the current anxiety for a very short time becomes less than the original. Under the anode anxiety during the whole time of current flow decreases, after open-circuit transient increases and soon reaches the source level.
Described under electrodes changes excitability Pfluger called elektrotokom. Changes observed under the cathode, called tatelektromasha, and under the anode - electromana.
Meanwhile, C. F. Verigo in 1883, has shown that increasing the excitability under the cathode is kept very short time, and then there is a decrease in excitability (Catholic depression). The higher the strength of current flowing through excitable tissue, the sharper expressed depression. Conclusion of Pfluger, as shown by C. F. Verigo, due to faulty production experience: when setting the threshold was summation of physical effects obtained from the cathode polarization current and current test, which was determined anxiety studied nerve. Further research in this direction confirmed the findings of the Century F. Verigo (Erlanger, Blair, 1938; Lorente de No, 1949). It was found that immediately after switching on the current Dorogova forces anxiety under the cathode increases steeply, and within 1-2 MS reaches a certain level at which lasts for a short time, then begins to fall (the steeper than the stronger current). This decrease anxiety caused by adaptation, i.e. the process directed towards easing the changes that caused the current.
Under the anode (Park, 1940) anxiety immediately falls, reaches over 1 MS minimum, after which it starts to rise, reaching out, however, the original value. The greater the current, the sharper expressed these changes.
Special attention deserves the fact that on the nerve, which in normal circulation, there is only a decrease in excitability, later the same relative increase does not occur.
As already noted above, according to the classical idea of elektroline, open circuit under the cathode anxiety is briefly lowered, and under the anode - rises. However, these provisions are, in our opinion, are wrong and need appropriate amendment. In both cases, Pfluger and other authors are not considered the phenomenon Peltier, the essence of which is the following. If the two parts of the body to make two electrodes from the DC source and skip the current (even for a very short time), and after turning it quickly (with switch) to connect them with microammeter, by the second circuit will reverse current trends.
Further study of this phenomenon showed that the passage of current through the body tissues under the anode become positively charged and under the cathode is negatively charged. When turning off the current oppositely charged parts of the body become a source of electromotive force the opposite direction. She was described Peltier (Peltier).