Axons may be covered in a layer made of cells called the myelin sheath. The sheath is made up of either oligodendrocytes or Schwann cells, both of which are types of glial cells. Myelin sheath increases the speed at which nerve impulses are transmitted from one nerve cell to another.
Gaps between each section of myelin sheath on the axon are known as Nodes of Ranvier. Sodium/potassium (Na+/K+) pumps are located here and