Question

Describe the characteristics of nerve impulse transmission (action potentials) along unmyelinated and myelinated axons.

Answer 1

Action potential is the nerve impulse actually.

In order to relate to the action potential,lets consider about resting potential first,the axonal membrane is maintained by the active transport of ions by the sodium-potassium pump which transports 3 Na+ outwards for 2K+ in to the cell.So the outer surface possess a +ve charge but inner surface is -ve charge,this is called polarised. And the electrical potential difference across the resting membrane is called the resting potential.

And when a stimulus is applied in the polarised membrane, the axonal membrane becomes permeable toNa+ ions resulting in rapid influx of Na+ ions followed by reversal of the polarity (meaning outer surface =-ve inner side=+ve.)this state is called depolarised.the electric potential across this ,is called action potential.