The level of stimulation necessary to start an action potential is known as the

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Multiple Choice

The level of stimulation necessary to start an action potential is known as the

Threshold is the minimum depolarization needed to trigger an action potential. When the neuron's resting potential (~-70 mV) is depolarized to about -55 mV, voltage-gated Na+ channels open, Na+ rushes in, and the rapid depolarization creates an action potential. Subthreshold stimuli fail to reach this critical level, so no spike occurs. Once threshold is reached, the response is all-or-nothing: the neuron fires a full action potential that propagates along the axon. The resting potential is simply the baseline state before any firing, and the refractory period is the brief time after an action potential during which the neuron is less excitable. The endocrine system isn’t about initiating action potentials in neurons.

Threshold is the minimum depolarization needed to trigger an action potential. When the neuron's resting potential (~-70 mV) is depolarized to about -55 mV, voltage-gated Na+ channels open, Na+ rushes in, and the rapid depolarization creates an action potential. Subthreshold stimuli fail to reach this critical level, so no spike occurs. Once threshold is reached, the response is all-or-nothing: the neuron fires a full action potential that propagates along the axon. The resting potential is simply the baseline state before any firing, and the refractory period is the brief time after an action potential during which the neuron is less excitable. The endocrine system isn’t about initiating action potentials in neurons.

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