Introduction

Neurons transmit electrical signals known as nerve impulses or action potentials. To efficiently and rapidly propagate these signals across long distances, many neurons are covered with a myelin sheath—a multi-layered fatty membrane wrapping around the axon. This myelination critically influences nerve conduction. This article uses the analogy of neurons as electrical wires to explain the key function of the myelin sheath in nerve impulse transmission.

The Myelin Sheath as an Electrical Insulator

• The myelin sheath acts similarly to the plastic insulation on electrical wires.

• It is composed of layers of lipid-rich membranes produced by Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS).kenhub+2

• Myelin sheath has high electrical resistance and low capacitance, which prevents ion leakage and limits current dissipation across the neuronal membrane.ncbi.nlm.nih

How Myelin Increases Conduction Speed

• By insulating the axon, myelin restricts the movement of ions across the membrane to small gaps called nodes of Ranvier.wikipedia+1

• The action potential “jumps” from node to node in a rapid process termed saltatory conduction.

• This jumping significantly speeds nerve impulse conduction compared to unmyelinated fibers where signals propagate continuously.kenhub+1

Why Myelin is Like an Electrical Insulator

Correct Answer

Among the options, the function of myelin sheath that best matches its role is:

(1) Insulator