How does the myelin sheath affect nerve impulse speed?

The myelin sheath significantly impacts the speed of nerve impulses, and its role in speeding up transmission is crucial for efficient communication within the nervous system. The myelin sheath is a fatty layer that surrounds the axons of many neurons. This insulation allows the electrical impulses (action potentials) to jump from one node of Ranvier to another through a process called saltatory conduction.

In myelinated neurons, these nodes are gaps in the myelin sheath where the axonal membrane is exposed. This arrangement leads to much faster conduction speeds compared to unmyelinated neurons, where the impulse travels continuously along the entire length of the axon. By providing insulation and facilitating the jump of impulses between these nodes, the myelin sheath drastically increases the speed of neural communication, enabling rapid responses and efficient processing of information.