Which ion does the resting membrane potential mostly depend

Which ion does the resting membrane potential mostly depend on? Thinking in terms of cell membrane properties, why is this the case? Why is an action potential an all-or-none event?

Solution

Answer:

Differential permeability of Na+ and K+ ions across the cell membrane gives rise to resting membrane potential. At rest, potassium ions (K+) can cross through the membrane easily but chloride ions (Cl-)and sodium ions (Na+) have a more difficult time crossing. This gives rise to net negative resting membrane potential.

An action potential an all-or-none event because there are no big or small action potentials in one nerve cell - all action potentials are the same size. Therefore, the neuron either does not reach the threshold or a full action potential is fired.

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