What is the role of myelin sheaths in nerve cells?

Myelin sheaths play a critical role in the functioning of nerve cells, primarily by increasing the speed at which electrical signals, or action potentials, propagate along the axon. Myelin is a fatty substance that wraps around the axon in segments, creating an insulating layer. This insulation allows for saltatory conduction, where the electrical impulse jumps from one node of Ranvier (the gaps in the myelin sheath) to the next, rather than traveling continuously along the entire length of the axon. This jumping mechanism significantly accelerates the transmission of signals compared to unmyelinated fibers, where the signal must traverse the entire membrane.

This increased signal speed is crucial for effective communication within the nervous system, enabling rapid responses and coordination between different parts of the body. Thus, the role of myelin sheaths is essential for the efficiency of neuronal signaling, greatly impacting overall nervous system function.