Question

An action potential is sure to fire, once ___ channels are open.

• A. Volatge gated Na+
• B. Voltage gated K+
• C. K+ leak channels
• D. Ligand gated Na+

Answer 1

The correct option is A Volatge gated Na+

An action potential is an all or none phenomenon, that is once the threshold potential of -55mV is reached it is sure to fire, if not there will be no action potential generated. The threshold potential is -55mV because at -55mV the voltage gated Na⁺ channels open, which sets off a positive feedback loop leading to opening of more voltage gated Na⁺ channels in the next segment of the neuron, forming the action potential.