Schwann Cells

Definition

Schwann cells are a type of glial cell found in the peripheral nervous system. They play a crucial role in the function and maintenance of nerve fibers, including the insulation and regeneration of axons.

5 Must Know Facts For Your Next Test

1. Schwann cells are responsible for the myelination of peripheral nerve fibers, which increases the speed of electrical impulse transmission.
2. In the PNS, Schwann cells form the myelin sheath around axons, whereas in the central nervous system, this function is performed by oligodendrocytes.
3. Schwann cells also play a crucial role in the regeneration of damaged peripheral nerves by providing structural and trophic support for the regrowth of axons.
4. The presence of Schwann cells is essential for the proper functioning of the neuromuscular junction, where motor neurons connect with muscle fibers.
5. Disruption of Schwann cell function or myelination can lead to various peripheral nerve disorders, such as Charcot-Marie-Tooth disease and Guillain-Barré syndrome.

Review Questions

• Explain the role of Schwann cells in nerve conduction.
  • Schwann cells are essential for the efficient transmission of electrical impulses along peripheral nerve fibers. They achieve this by wrapping their plasma membrane around the axons, forming a myelin sheath. The myelin sheath acts as an insulator, increasing the speed of action potential propagation through the process of saltatory conduction. This allows for faster and more efficient communication between the nervous system and the rest of the body.
• Describe how Schwann cells contribute to the regeneration of damaged peripheral nerves.
  • Schwann cells play a crucial role in the regeneration of peripheral nerves following injury. After nerve damage, Schwann cells dedifferentiate and proliferate, forming bands of Büngner that guide the regrowth of severed axons. Schwann cells also secrete growth factors and provide structural support to facilitate the reconnection of the injured nerve fibers. This remarkable ability of Schwann cells to support nerve regeneration is essential for the restoration of function in the peripheral nervous system.
• Analyze the significance of the differences between Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.
  • The primary difference between Schwann cells and oligodendrocytes is their location and the specific nervous system they support. Schwann cells are found in the peripheral nervous system and are responsible for myelinating peripheral nerve fibers, whereas oligodendrocytes are present in the central nervous system and myelinate the axons of central nervous system neurons. This distinction is crucial, as the regenerative capacity of the peripheral nervous system is much greater than that of the central nervous system, largely due to the unique properties and functions of Schwann cells. Understanding these differences is essential for developing targeted treatments for various neurological disorders affecting either the central or peripheral nervous system.

Related terms

Myelination: The process by which Schwann cells wrap their plasma membrane around axons, forming a myelin sheath that increases the speed of electrical impulse transmission.

Axon:

The long, slender projection of a neuron that transmits electrical signals to other cells.

Peripheral Nervous System (PNS): The part of the nervous system that consists of the nerves and ganglia outside the brain and spinal cord, connecting them to the rest of the body.