Question

During the propagation of a nerve impulse, the action potential results from the movement of:

• A. K⁺ ions from extracellular fluid to intracellular fluid
• B. Na⁺ ions from extracellular fluid to intracellular fluid
• C. K⁺ ions from intracellular fluid to extracellular fluid
• D. Na⁺ ions from intracellular fluid to extracellular fluid

Answer 1

Answer: (B)

The total sum of physio-electrochemical changes that takes place along the length of the nerve fibre is known as nerve impulse. Change in potential due to the stimulation of nerve fibre is called an action potential. During propagation of nerve impulse, Na⁺ enters inside, so (+ve) charge is formed inside the membrane. K⁺ ions come out.