How is an action potential transmitted?

Hello, I'm a neuroscience enthusiast with a keen interest in the mechanisms of neural communication. Let's delve into the process of how an action potential is transmitted. An action potential is an electrical signal that travels along a neuron's axon. The transmission of an action potential involves several key steps: 1. Resting Potential: At rest, a neuron has a negative charge inside the cell relative to the outside, known as the resting potential. This is primarily due to the sodium-potassium pump, which actively transports sodium ions out of the cell and potassium ions into the cell. 2. Stimulus: When a stimulus is strong enough, it can cause some of the voltage-gated sodium channels in the neuron's membrane to open. This allows sodium ions to flow into the cell, causing the membrane potential to become more positive, a process known as depolarization. 3. Threshold: If the depolarization is sufficient to reach a certain level, known as the threshold, it triggers the opening of more sodium channels, causing a rapid influx of sodium ions. This results in a rapid reversal of the membrane potential, making the inside of the cell positive relative to the outside. 4. Action Potential: This rapid depolarization is the action potential. It travels along the axon, and as it does, it causes the opening of sodium channels in adjacent areas of the axon, propagating the action potential down the axon. 5. Repolarization: After the peak of the action potential is reached, the sodium channels close and potassium channels open, allowing potassium ions to flow out of the cell. This helps to repolarize the membrane, bringing it back to its resting state. 6. Refractory Period: There is a brief period after an action potential during which the neuron cannot generate another action potential. This is known as the refractory period and ensures that action potentials only travel in one direction along the axon. 7. Synaptic Transmission: Once the action potential reaches the axon terminal, it triggers the release of neurotransmitters into the synaptic cleft, which can then go on to stimulate the next neuron in the sequence.

Transmission of a signal within a neuron (in one direction only, from dendrite to axon terminal) is carried out by the opening and closing of voltage-gated ion channels, which cause a brief reversal of the resting membrane potential to create an action potential.