Medullary sheath

Medullary Sheath

The Medullary Sheath is a critical component of the nervous system, specifically in the structure of neurons. It is also known as the myelin sheath, and it plays a vital role in the transmission of electrical impulses along the nerve fibers.

Structure

The medullary sheath is composed of lipids and proteins, forming a white, fatty insulating layer around the axon of a neuron. This sheath is not continuous along the length of the axon; instead, it is segmented, with gaps known as Nodes of Ranvier. These nodes play a crucial role in the speed and efficiency of electrical impulse transmission.

Function

The primary function of the medullary sheath is to increase the speed at which electrical impulses propagate along the nerve fiber. This is achieved through a process known as saltatory conduction, where the electrical impulse jumps from one Node of Ranvier to the next, rather than traveling the entire length of the axon.

In addition to speed, the medullary sheath also provides protection and insulation to the axon, preventing electrical impulses from escaping and ensuring they reach their intended destination.

Clinical Significance

Damage or degeneration of the medullary sheath can lead to several neurological disorders, such as Multiple Sclerosis, where the immune system mistakenly attacks the myelin sheath, and Charcot-Marie-Tooth Disease, a group of inherited disorders that affect the peripheral nerves.

See Also

• Neuron
• Nervous System
• Multiple Sclerosis
• Charcot-Marie-Tooth Disease