Final answer:
The myelin sheath is a fatty tissue layer segmentally encasing the axons of some neurons, enabling faster transmission of neural impulses. It acts as insulation, similar to the plastic covering of electrical wires. The myelin sheath has small gaps called Nodes of Ranvier that allow the impulses to travel rapidly.
Step-by-step explanation:
The fatty tissue layer segmentally encasing the axons of some neurons, enabling vastly greater transmission speed as neural impulses hop from one node to the next, is the myelin sheath.
The myelin sheath is a lipid-rich insulating substance that surrounds the axons of many neurons, allowing for faster transmission of electrical signals. It acts like a layer of insulation, similar to the plastic encasing an electrical wire.
The myelin sheath is not continuous and has small gaps, called Nodes of Ranvier, which allow nerve impulses to skip along the axon very rapidly. This sheath is crucial for the normal operation of neurons within the nervous system.