What term describes the protective coat of fat and protein that wraps around the axon?

The myelin sheath is the correct term that describes the protective coat of fat and protein wrapping around the axon of many neurons. This sheath plays a critical role in the nervous system; it acts as an insulator, allowing for the rapid transmission of electrical signals along the axon. By increasing the speed at which impulses travel, the myelin sheath enhances communication between neurons, making it essential for efficient functioning of the nervous system.

In addition to facilitating faster signal transmission, the myelin sheath also serves to protect the axon from damage. Without this protective layer, nerve signals could be slower and less efficient, possibly leading to impaired nerve function. Conditions such as multiple sclerosis, which involve the degradation of the myelin sheath, illustrate the critical importance of this structure to overall neurological health and function.