The physiology of nerve conduction involves the generation and propagation of an electrical signal, called an action potential, along the axon of a neuron. This process relies on the movement of ion

Here's a description of the physiology of nerve conduction: The physiology of nerve conduction involves the generation and propagation of an electrical signal, called an action potential, along the axon of a neuron. This process relies on the movement of ions across the neuronal membrane. 1. Resting Membrane Potential: A neuron at rest maintains a resting membrane potential, typically around -70 mV, where the inside of the cell is negative relative to the outside. This is established and maintained by the sodium-potassium pump (which actively transports 3 Na^+ ions out and 2 K^+ ions in) and the differential permeability of the membrane to K^+ (high) and Na^+ (low) through leak channels. 2. Depolarization and Action Potential Generation: When a stimulus reaches a neuron and causes the membrane potential to reach a threshold potential (e.g., -55 mV), voltage-gated Na^+ channels open rapidly. Na^+ ions rush into the cell, causing the inside of the membrane to become positive (depolarization), leading to the rising phase of the action potential. 3. Repolarization: As the membrane potential reaches its peak (around +30 mV), the voltage-gated Na^+ channels inactivate, and voltage-gated K^+ channels open more slowly. K^+ ions flow out of the cell, making the inside of the membrane negative again (repolarization), which is the falling phase of the action potential. 4. Hyperpolarization (Undershoot): The voltage-gated K^+ channels remain open for a short period after the membrane potential returns to resting levels, causing a brief period of hyperpolarization where the membrane potential becomes even more negative than the resting potential. The sodium-potassium pump then restores the ion gradients. 5. Propagation of the Action Potential: The action potential propagates along the axon as the depolarization at one point triggers the opening of voltage-gated Na^+ channels in the adjacent region of the membrane. In myelinated axons, the action potential "jumps" from one Node of Ranvier to the next (a process called saltatory conduction), significantly increasing the speed of conduction. In unmyelinated axons, the action potential propagates continuously along the membrane. That's 2 down. 3 left today — send the next one.