Question

The average resting membrane potential of an axon is ________?

1) -70 mV
2) +30 mV
3) 0 mV
4) -85 mV

Answer 1

The average resting membrane potential of an axon is -70 mV, sustained by the selective permeability of the cell membrane and the action of the sodium-potassium pump.

Step-by-step explanation:

The average resting membrane potential of an axon is -70 mV. This electrical potential is due to the differences in the concentration of ions across the cell membrane. Potassium ions, which have a higher concentration inside the neuron, can freely move out through potassium channels, while sodium ions are more concentrated outside the cell. Leakage channels and the sodium-potassium pump work together to maintain this potential; the pump expends ATP to move three sodium ions out of the cell and two potassium ions into the cell, thus upholding the negative charge inside relative to the outside. The resting membrane potential is crucial for the physiological response to various chemical and electrical signals.