Question

An action potential in the nerve fibre is produced when positive and negative charges on outside and inside of the axon are reversed because

• A. more potassium ions enter the axon as compared to sodium ions leaving it
• B. more sodium ions enter the axon is compared to potassium ions leaving it
• C. all potassium ions leave the axon
• D. all sodium ions enter the axon

Answer 1

The correct option is B more sodium ions enter the axon is compared to potassium ions leaving it

When a nerve fibre is stimulated, its membrane becomes more permeable to sodium ions, hence more sodium enter the axon than potassium ions leaving it.