is produced when the membrane potential is depolarized to 0 mV.

is the result of a transient increase in K⁺ permeability and Cl^- permeability.

is the result of a transient increase in Na⁺ permeability and a decrease in K⁺ permeability.

is associated with an increase in the electrical resistance of the nerve membrane.

is always of a fixed size regardless of the strength of the stimuli eliciting the action potential.