What is the function of the myelin sheath?

The myelin sheath plays a crucial role in the nervous system by acting as an insulating layer around nerve fibers, particularly axons. This insulation is essential for the rapid transmission of electrical impulses along the nerve fibers. The myelination process allows the impulses to jump between the nodes of Ranvier — small gaps in the myelin sheath — which significantly increases the speed of conduction compared to unmyelinated fibers. This efficient signaling is vital for proper communication within the nervous system, enabling quick reflexes and coordination of bodily functions.

In contrast, other options refer to different biological functions. Connecting muscle to bone is the role of tendons, hormones are transmitted through various endocrine pathways and are not related to the myelin sheath, and blood cells are produced in the bone marrow, which is a completely different tissue type and function. Understanding the function of the myelin sheath in insulation helps highlight its importance in maintaining the overall efficacy of neuronal communication.