Myelin Sheath

The myelin sheath is a protective covering that surrounds nerve fibers and facilitates the transmission of electrical impulses along the nerve cells. It is composed of specialized cells called oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.

Structure and Function

The myelin sheath is made up of layers of cell membrane that form a lipid-rich insulating material. This insulation allows for the rapid conduction of nerve impulses, as it prevents the loss of electrical signal strength as it travels along the nerve fiber. The gaps in the myelin sheath, known as nodes of Ranvier, help to speed up the transmission of nerve impulses by allowing for saltatory conduction.

Importance

The myelin sheath plays a crucial role in the proper functioning of the nervous system. Damage to the myelin sheath, as seen in conditions such as multiple sclerosis, can lead to disruptions in nerve signaling and impaired motor and sensory function.

Study Guide

1. What is the composition of the myelin sheath?
2. Describe the role of the myelin sheath in the transmission of nerve impulses.
3. Differentiate between oligodendrocytes and Schwann cells in the formation of the myelin sheath.
4. Explain the significance of the nodes of Ranvier in nerve impulse conduction.
5. Discuss the impact of myelin sheath damage on nervous system function.