PATHOLOGY

Detailed explanation-1: -This occurs when the threshold potential (-55 mV) is reached, this causes a rapid opening in the voltage-gated sodium channels leading to an influx of sodium ions into the cell.

Detailed explanation-2: -The threshold equation Thus, when the neuron is depolarized, Na channels inactivate (h decreases) and the threshold increases: the threshold adapts to the membrane potential.

Detailed explanation-3: -To begin an action potential, the membrane potential must change from the resting potential of approximately-70mV to the threshold voltage of-55mV. Once the cell reaches threshold, voltage-gated sodium channels open and being the predictable membrane potential changes describe above as an action potential.

Detailed explanation-4: -The minimum stimulus needed to achieve an action potential is called the threshold stimulus. The threshold stimulus causes the membrane potential to become less negative (because a stimulus, no matter how small, causes a few sodium channels to open and allows some positively-charged sodium ions to diffuse in).