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How the resting membrane potential is established in a neuron. Skip to main content If you're seeing this message, it means we're having trouble loading external resources on our website.
For this reason, membrane potential for excitable cells when they are not excited is called the resting membrane potential, while its changes are associated with an action potential. Key facts about the membrane potential
The membrane potential will stay at the resting voltage until something changes. To begin an action potential, the membrane potential must change from the resting potential of approximately -70mV to the threshold voltage of -55mV.
The return of the membrane potential to the resting potential is called the repolarization phase. There is also a phase of the action potential during which time the membrane potential can be more negative than the resting potential.
An action potential is defined as a sudden, fast, transitory, and propagating change of the resting membrane potential. Only neurons and muscle cells are capable of generating an action potential; that property is called the excitability .
Figure 12.23 Graph of Action Potential Plotting voltage measured across the cell membrane against time, the action potential begins with depolarization, followed by repolarization, which goes past the resting potential into hyperpolarization, and finally the membrane returns to rest.
These two events commonly occur in excitable cells that have an action potential, whereas most other cells have a constant resting membrane potential that does not change. Most are familiar with the concept of depolarization when referring to an action potential.
Figure 1. Voltage-gated ion channels open in response to changes in membrane voltage. After activation, they become inactivated for a brief period and will no longer open in response to a signal. This video discusses the basis of the resting membrane potential.
Transmission of a signal within a neuron (from dendrite to axon terminal) is carried by a brief reversal of the resting membrane potential called an action potential. When neurotransmitter molecules bind to receptors located on a neuron’s dendrites, ion channels open.
Normally, the cell’s interior is negative, compared to its outside. This state is the resting membrane potential of about -60mV. A neuronal action potential gets generated when the negative inside potential reaches the threshold (less negative).