An action potential is a rapid change in the electrical charge of a neuron, which allows it to send signals throughout the body. When a neuron is stimulated, sodium ions rush into the cell, causing the inside to become more positive. This sudden shift in charge travels along the neuron, enabling communication between nerve cells and ultimately leading to muscle contractions or other responses. Once the action potential reaches the end of the neuron, it triggers the release of neurotransmitters, which are chemicals that transmit signals to other neurons or muscles. This process is essential for functions like movement, sensation, and thought, making action potentials a fundamental aspect of the nervous system's operation.