Final answer:
An action potential is a rapid change in the membrane potential of a neuron that involves depolarization, repolarization, hyperpolarization, and a return to the resting state, driven by the opening and closing of ion channels.
Step-by-step explanation:
The concept of an action potential is crucial to understanding how neurons communicate. An action potential occurs when a neuron sends information down an axon, away from the cell body. The membrane potential of a neuron is normally at a resting state, but when an action potential occurs, there is a rapid change in this potential. This change includes several stages:
- Depolarization: Triggered by the opening of the voltage-gated sodium channels, allowing Na+ ions to rush into the neuron.
- Repolarization: Following depolarization, voltage-gated potassium channels open, allowing K+ ions to leave the neuron and start restoring the negative membrane potential.
- Hyperpolarization: The membrane potential temporarily becomes more negative than the resting potential.
- Return to resting potential: The membrane potential returns to its resting state, mainly due to the action of the sodium-potassium pump and the closing of potassium channels.
Each phase of the action potential is correlated with the opening and closing of specific ion channels, which control the entry and exit of ions from the neuron, resulting in changes in the membrane potential. These ion movements are primarily due to facilitated diffusion through gated ion channels.