What is the Difference Between Resting Potential and Action Potential?

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The resting potential and action potential are two different electrical states of neurons and muscle cells, which are essential for understanding how these cells function and communicate with each other.

Resting Potential:

  • The resting potential is the membrane potential of an excitable cell (e.g., a neuron or muscle cell) when it is at rest.
  • It is caused by the unequal distribution of ions inside and outside the cell, with relatively more sodium ions outside the neuron and more potassium ions inside.
  • The resting potential of a neuron is about -70 mV, meaning that the inside of the neuron is negatively charged compared to the outside.
  • This state is maintained by ion transporters, such as the sodium-potassium pump, which moves three sodium ions out of the neuron for every two potassium ions it brings in.

Action Potential:

  • An action potential is a rapid change in the membrane potential of a neuron or muscle cell, which occurs when the cell sends information down an axon, away from the cell body.
  • It is generated by the movement of several ion species through various ion channels and transporters, resulting in different electrostatic charges across the cell membrane.
  • The action potential is an "all-or-nothing" event, meaning that once the threshold potential is reached, the neuron always completely depolarizes.
  • The duration of an action potential is dependent on the cell type, with neurons having an action potential duration of roughly 1 ms, skeletal muscle cells around 10 ms, and cardiac muscle cells about 300 ms.

In summary, the resting potential is the stable, negative membrane potential that maintained by ion transporters in neurons and muscle cells, while the action potential is a rapid change in membrane potential that occurs when these cells send information down an axon.

Comparative Table: Resting Potential vs Action Potential

Here is a table comparing the differences between resting potential and action potential:

Resting Potential Action Potential
Resting potential is the relatively stable, negative charge of a neuron when it is not sending signals. Action potential is a sequence of changes in the voltage-gated ion channels in a neuronal membrane, resulting in a temporary reversal of the membrane potential.
Resting potential is a result of different concentrations of ions inside and outside the cell. Action potential occurs due to the transport of charged particles through the cell membrane, leading to a change in potential.
The resting membrane potential of a neuron at rest is approximately -70 mV, but this value can vary by neuron type and species. Action potentials are considered an "all-or-nothing" event, with a typical amplitude of around 100 mV, depending on the type of nerve cell.
Resting potential is a constant value when a cell is at rest. Action potentials are generated when a neuron reaches a specific threshold potential (approximately -50 mV).
The resting potential is maintained by ion transporters, such as the Na+/K+-ATPase. The generation of action potentials is affected by the permeability of adjacent membrane regions, which can influence the depolarization of the neuron.