In our body nerve impulses are …

TRANSMISSION OF NERVE IMPULSE

• Normal State/ Polarized State

In the normal (resting) condition, the outer side of the nerve fiber carries positive (+) charge. This is called polarized state. At this state more Na+ ions are outside the the axon membrane.

• On Stimulation (Depolarized State),

The axon membrane at the spot where stimulation takes place becomes more permeable to Na+ which move inwards and cause loss of Polarization, i.e., they become excited (depolarized state).

• Repolarization

Meanwhile, the previous region become Repolarized due to active transport of Na+ ions again to the outside. (This transport is achieved by using energy thru ATP and its called ‘‘Sodium Pump’’).

‘‘Conduction of nerve impulse is a wave of depolarization followed by repolarization’’

Which means conduction of nerve impulse takes place by the movement of Na+ ions in and out of the axon membrane. While depolarization, Na+ ions move inside the membrane, and during repolarization they move outside the membrane due to the active transport of Na+ ions using energy thru ATP.