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The resting potential


What is the resting potential?

The resting potential describes the state of the negative potential of an unexperienced nerve cell. This negative potential can be summed up Charge imbalance of the ions between extracellular space and cytoplasm.
Without a maintenance of the resting potential, the transmission of nerve implants within the action potential would not be possible.
Measuring the tension of the cell interior of a nerve cell axon gives a negative potential of approximately -70 mV (millivolts). Reasonably, this is due to an unequal distribution of ion concentration outside and within the axon.
In the cell interior of the axon are mainly K+ (Potassium) and A- (organic anions) ions. Outside the membrane, one encounters Na in particular+ (Sodium) and Cl- (Chloride) ions. The inside of the cell and the cell exterior are replaced by a semipermeable membrane separated from each other.

Viewed individually, the total charges in the cell interior and cell walls are balanced. Means: Inside the cell the charges of K are equal+ and A- out; The charges of Na are similar in the cellular state+ and Cl- out.
Causal for the resting membrane potential is now the charge difference between these two charges (intracellular vs. extracellular). This in turn, as already mentioned, is due to the unequal distribution of the positively and negatively charged ions between the cell interior and the cell nucleus.
The neuron must first build up a negative charge in the interior and then hold it permanently. Exist in the membrane Potassium, chloride and sodium channels, The latter two are closed at rest potential. Due to Brownian motion, K moves+ Ions out through the open potassium channels (and only outward, reverse entry is prevented by the ion channels), which makes the charge potential in the axon more negative (hence it becomes more positive in the outer region).
From the outside, but still Na+Ions through so-called leakage currents into the cell and would sooner or later provide for a compensation of the charges of extracellular space and cytoplasm, whereby the rest potential would be destroyed. The reason for this is the diffusion of particles. Molecules and charge carriers always strive for a balance of concentration.
In the membrane located sodium-potassium pumps provide for a return transport of eingemömten Na+Ions. Under ATP consumption will be three Na+Ions transported to the outside and in return two K+Ions inside. In this way, the negative membrane potential of about -70mV is maintained. Why that is necessary, you will learn at the action potential