Describe the genesis of different phases of nerve action potential.« Back to Questions List

Posted by Tarik Paik
Asked on November 9, 2018 2:15 pm

When is a nerve fibre is stimulated optimally, a series of potential changes occur at the point of stimulation which is called action potential. It has different phases like spike potential and after potentials which consists of negative and positive after potentials. This changes are mainly due to ionic fluxes. The events are as follows :
Initially at the stimulated point ,the resting potential slowly decreased by about 15 mv and reaches a level called ‘firing level’.It is due to electronic depolarization. When the firing level is reached, voltage geted Na+ channel open. A rapid Na+ influx occurs leading to upstroke of spike. Then k+ efflux stars which initially occurs very rapidly .This causes down stroke of the spike .This is followed by slow k+ efflux that causes development of negative after potential .At the end of this, resting membrane potential is reached. At the point, the membrane potential is the storage but the ionic status is opposite in nature .

Posted by aalkhadiza
Answered On November 9, 2018 2:20 pm