Schwann cells

Definition

Schwann cells are specialized glial cells in the peripheral nervous system that play a critical role in the formation of myelin sheaths around axons. These cells not only facilitate the rapid conduction of nerve impulses but also support the regeneration of damaged nerves, making them essential for proper nervous system function.

5 Must Know Facts For Your Next Test

1. Schwann cells are crucial for myelination in the peripheral nervous system, wrapping around axons to form the myelin sheath, which increases signal transmission speed.
2. Each Schwann cell can myelinate a single segment of an axon, and multiple Schwann cells are needed to cover an entire axon.
3. In addition to myelination, Schwann cells produce neurotrophic factors that promote neuronal growth and repair following injury.
4. Unlike oligodendrocytes in the central nervous system, which can myelinate multiple axons, Schwann cells only myelinate one axon at a time.
5. Damage to Schwann cells can lead to peripheral neuropathies, resulting in symptoms like numbness, weakness, or pain in affected limbs.

Review Questions

• How do Schwann cells contribute to the process of nerve impulse transmission in the peripheral nervous system?
  • Schwann cells contribute to nerve impulse transmission by forming myelin sheaths around axons in the peripheral nervous system. This myelination increases the speed at which electrical signals travel along the axon through a process known as saltatory conduction, where impulses jump between nodes of Ranvier. The presence of Schwann cells allows for efficient communication between neurons and helps maintain proper nerve function.
• Discuss the role of Schwann cells in nerve regeneration and how they differ from other types of glial cells.
  • Schwann cells play a vital role in nerve regeneration by providing a supportive environment for injured neurons. They release neurotrophic factors that encourage neuronal survival and growth, and they help guide regenerating axons to their target tissues. This regenerative capacity contrasts with oligodendrocytes in the central nervous system, which do not support regeneration as effectively due to their different structure and function.
• Evaluate the implications of Schwann cell dysfunction on peripheral nerve health and overall physiological processes.
  • Dysfunction of Schwann cells can lead to various peripheral neuropathies, significantly impacting nerve health and physiological processes. When Schwann cells fail to properly myelinate axons or support nerve regeneration, patients may experience symptoms like pain, weakness, or sensory loss. This impairment can disrupt motor functions and alter sensory perceptions, demonstrating how essential Schwann cells are for maintaining overall nervous system integrity and functionality.

Related terms

Myelin: A fatty substance that insulates nerve fibers, allowing for faster transmission of electrical signals along the axon.

Neuroglia: Supportive cells in the nervous system that provide structural and functional support to neurons, including Schwann cells.

Axon: The long, slender projection of a neuron that conducts electrical impulses away from the neuron's cell body.