Question

Which cellular channels open immediately after the peak of action potential?

• A. Sodium
• B. Potassium
• C. Both sodium and potassium
• D. Calcium

Answer 1

The correct option is B Potassium

Immediately after the peak of action potential, the sodium channel closes and potassium channel opens, allowing potassium ions to flow out of the cell to restore the resting potential of the membrane. The rise in the stimulus-induced permeability to Na${}^{+}$ is extremely short lived. It is quickly followed by a rise in permeability to
K${}^{+}$. Within a fraction of a second, K${}^{+}$ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation.