لخّصلي

The establishment of a resting membrane potential and its dependence on ion gradients and ion permeability are properties of almost all cells.Whereas a nonexcitable cell that has beentemporarily and slightly depolarized will simply return toits original resting membrane potential, an electricallyexcitable cell that is depolarized to the same degree willrespond with an action potential.The unique feature of electrically excitable cells their response to membranedepolarization.

The establishment of a resting membrane potential and its dependence on ion gradients and ion permeability are properties of almost all cells. The unique feature of electrically excitable cells their response to membranedepolarization. Whereas a nonexcitable cell that has beentemporarily and slightly depolarized will simply return toits original resting membrane potential, an electricallyexcitable cell that is depolarized to the same degree willrespond with an action potential.
Electrically excitable cells produce an action potentialbecause of the presence of voltage-gated channels in theplasma membrane. To see how nerve cells communicatesignals electrically, we need to understand the characteristics of the ion channels in the nerve cell membrane, asubject to which we now turn.