Which Ion Determines the Resting Membrane Potential of Nerve and Muscle

Question

Which ion determines the resting membrane potential of nerve and muscle?
A) Sodium
B) Calcium
C) Hydrogen
D) Potassium

Accepted Answer

The resting membrane potential of nerve and muscle is determined by the concentration gradient and selective permeability of potassium ions (K+). The intracellular concentration of K+ is higher compared to the extracellular concentration, leading to an electrochemical gradient that tends to pull K+ out of the cell. This creates a negative charge inside the cell, which balances the positive charge outside, resulting in a resting membrane potential around -70mV. Therefore, potassium ions (K+) are the ion that determines the resting membrane potential of nerve and muscle.