Chapter 12.4, Problem 16BYGO

Summary Introduction

Introduction:

 An action potential is an electrical impulse used for information passage between the nerve cell and muscle cell. A slight change in the potential of the resting membrane generated by a stimulus that opens a sodium gate in the nerve cell is called as the local potential. It occurs only when there is a high density of ion channels. Approximately, 50 to 75 channels/ µm² are seen in the soma, which is not enough to generate an action potential. The trigger zone has 350 to 500 channels/ µm². If a local potential in the excitatory state spreads to the trigger zone and if it is strong enough till its arrival, channels can be opened and action potential can be generated. The local potential is produced by voltage-gated ion channels on the dendrite and soma, may be positive (depolarized) or negative (hyperpolarized).