Question

The "threshold potential" of a membrane is the ______? A) lowest frequency of action potentials a neuron can produce B) minimum depolarization needed to produce an all-or-none action potential C) minimum hyperpolarization needed to prevent the occurrence of action potentials D) peak amount of depolarization seen in an action potential

Answer 1

The threshold potential of a membrane is the minimum depolarization necessary to trigger an action potential, which is an all-or-nothing event, and all action potentials reach the same peak voltage despite stimulus intensity.

Step-by-step explanation:

The "threshold potential" of a membrane is the minimum depolarization needed to produce an all-or-none action potential. This is a critical level that the membrane potential must reach for an action potential to occur, and it works on an all-or-nothing principle.

The threshold potential is generally about 15 millivolts (mV) more positive than the cell's resting membrane potential. If the threshold is not reached, no action potential is triggered; if it is surpassed, an action potential is generated, and the neuron will depolarize to a membrane potential of approximately +30 mV during the process. Despite the intensity of the stimulus, once the threshold is crossed, the magnitude of the action potential does not increase—it always peaks at the same voltage.