What is an action potential?

An action potential is a rapid electrical signal that travels along the axon of a neuron. It is characterized by a sudden change in the membrane potential, which occurs when a neuron depolarizes and then repolarizes. This process is essential for the transmission of signals in the nervous system, as it allows neurons to communicate with one another by propagating impulses over long distances.

The action potential begins when a neuron's membrane reaches a threshold potential, triggering the opening of voltage-gated sodium channels. Sodium ions flow into the cell, causing depolarization. Following this surge, potassium channels open, allowing potassium ions to exit the cell and restoring the resting membrane potential through repolarization. This sequence generates a wave of electrical activity that moves down the axon, leading to the release of neurotransmitters at the synapse, where communication with other neurons occurs.

Understanding this process is crucial for grasping how the nervous system functions, as it underpins all neuronal communication and is fundamental to activities such as reflexes and muscle contraction.