How does the myelin sheath affect nerve impulses?

The myelin sheath is a protective layer that surrounds the axons of many neurons, consisting primarily of lipid-rich substances. Its primary role is to increase the speed of electrical impulses along the axon through a process known as saltatory conduction.

In neurons that are myelinated, the myelin sheath acts as an insulator, allowing the electrical signal, or action potential, to jump from one Node of Ranvier (gaps in the myelin sheath) to another. This jumping significantly accelerates the transmission of nerve impulses compared to unmyelinated neurons, where the action potential must travel continuously along the entire length of the axon.

By enhancing the speed at which nerve impulses can travel, myelin sheaths play a crucial role in maintaining efficient communication between neurons, which is essential for rapid reflexes and motor control. This mechanism is vital for the proper functioning of the nervous system and affects everything from muscle movement to sensory perception.