The opening of which of the following types of ion channels will lead to a depolarization? A chemically gated sodium channel 2) a voltage gated sodium channel 3) A mechanically gated sodium channel 4) All of them

The opening of a voltage gated sodium channel will lead to a depolarization.

Explanation:

When the membrane potential of the membrane reaches the threshold of - 55mV - due to action potential or summation of smaller action potentials - the sodium channels in the membrane rapidly open causing rapid depolarization of the cell membrane as sodium ions rush across the membrane into the cell. This is an example of how electric impulse is carried across a neuron. When the membrane potential reaches into the positive, + 33mV, the membrane is completely depolarized and energy is required to pump out the sodium ions to regain the - 70mV resting membrane potential.