During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric charge ?

Options

A. First positive, then negative and continue to be negative
B. First negative, then positive and continue to be positive
C. First positive, then negative and again back to positive
D. First negative, then positive and again back to negative

Answer

D

Explanation

At resting potential (polarised phase), the inside of the plasma membrane is negatively charged (-70 mV).As the stimulus reaches, it becomes positively charged (+45 mV, depolarised phase). As impulse passes away, it regains its original ionic distribution and again becomes negatively charged.