Nerve Conduction Board Practice Test 2025 – Complete Exam Prep

The myelin sheath plays a crucial role in the conduction of nerve impulses by increasing the speed at which these impulses travel along the axon. Myelin is a fatty substance that wraps around the axons of many neurons, creating an insulating layer. This insulation is essential because it prevents the loss of electrical signals and allows the impulses to jump between gaps in the myelin sheath, known as nodes of Ranvier. This process is called saltatory conduction.

As a result, myelinated fibers can conduct impulses much more rapidly compared to unmyelinated fibers, where the action potentials must travel continuously along the entire length of the axon. By increasing conduction speed, myelin enables more efficient communication between nerve cells, facilitating faster reflexes and responses within the nervous system.

The other options do not accurately describe the primary function of the myelin sheath. While it does provide some protection to the nerve, that is not its main role in conduction. Similarly, while depolarization is crucial for nerve impulse transmission, the myelin sheath does not directly ensure depolarization. Therefore, the primary and correct function of the myelin sheath in nerve conduction is its ability to increase the speed of conduction.