Myelin Sheath

The myelin sheath is a protective covering that surrounds the axons of nerve cells. It is made up of a type of cell called oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. The primary function of the myelin sheath is to insulate and protect the nerve fibers, as well as to facilitate the transmission of nerve impulses.

Structure of Myelin Sheath

The myelin sheath is composed of multiple layers of the cell membrane of oligodendrocytes or Schwann cells wrapped around the axon in a spiral fashion. These layers form a lipid-rich substance that acts as an electrical insulator, allowing for faster conduction of nerve impulses along the axon.

Function of Myelin Sheath

The main function of the myelin sheath is to increase the speed and efficiency of nerve impulse conduction. It does so by insulating the axon, preventing the leakage of electrical currents and allowing the nerve impulse to "jump" from one node of Ranvier to the next in a process called saltatory conduction. This results in faster transmission of signals along the nerve fiber.

Importance of Myelin Sheath

The presence of a well-developed myelin sheath is crucial for the proper functioning of the nervous system. It enables rapid communication between different parts of the body and is essential for motor coordination, sensory perception, and cognitive functions.

Related Disorders

Damage or degradation of the myelin sheath can lead to various neurological disorders, such as multiple sclerosis, Guillain-Barré syndrome, and Charcot-Marie-Tooth disease. These conditions can result in impaired nerve conduction, leading to symptoms such as muscle weakness, loss of sensation, and coordination difficulties.

Study Guide: Myelin Sheath

1. What is the composition of the myelin sheath?
2. Explain the function of the myelin sheath in nerve impulse conduction.
3. Describe the structure of the myelin sheath and how it facilitates saltatory conduction.
4. Discuss the importance of the myelin sheath in the proper functioning of the nervous system.
5. Identify and explain at least two neurological disorders related to damage of the myelin sheath.