Question

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?

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

Answer 1

The correct option is B First negative, then positive and again back to negative

The signal that travels along the length of a nerve fibre and is the means by which information is transmitted through the nervous system is called nerve impulse.
During the resting or normal phase, the inner side of the plasma membrane of a nerve fibre is negatively charged.
On arrival of a stimulus or action potential, the inner side of the nerve fibre carries a positive charge.
As this stimulus is transmitted, the nerve fibre resturns back to its resting potential and hence develops a negative charge on the inner side of the plasma membrane.