Schwann cells

Definition

Schwann cells are specialized glial cells in the peripheral nervous system that are essential for the formation of myelin sheaths around nerve fibers. These cells not only facilitate the rapid transmission of electrical signals along axons but also play a crucial role in the repair and regeneration of damaged neurons. By insulating the axons, Schwann cells enhance the efficiency of nerve impulse conduction and contribute to overall neuronal function.

5 Must Know Facts For Your Next Test

1. Each Schwann cell typically myelinates a single segment of an axon in the peripheral nervous system, unlike oligodendrocytes, which can myelinate multiple axons in the central nervous system.
2. Schwann cells play a vital role in nerve regeneration; they help create a pathway for regenerating axons and release growth factors that support repair processes.
3. In addition to myelination, Schwann cells can also function as supportive cells that maintain homeostasis and provide metabolic support to neurons.
4. Schwann cells are derived from neural crest cells during embryonic development, contributing to their unique properties and functions within the peripheral nervous system.
5. Demyelination diseases, such as Guillain-Barré syndrome, involve damage to Schwann cells, leading to impaired nerve function and symptoms like muscle weakness and sensory loss.

Review Questions

• How do Schwann cells contribute to the function and repair of peripheral nerves?
  • Schwann cells are crucial for both the myelination of peripheral nerves and their repair after injury. They wrap around axons to form myelin sheaths, which enhance electrical signal transmission and speed. When nerves are damaged, Schwann cells facilitate repair by guiding regenerating axons along their original pathways and releasing growth factors that promote healing and recovery.
• Compare and contrast Schwann cells and oligodendrocytes in terms of their structure and function.
  • While both Schwann cells and oligodendrocytes are responsible for forming myelin sheaths around axons, they differ significantly in their structure and location. Schwann cells are found in the peripheral nervous system and typically myelinate single segments of individual axons. In contrast, oligodendrocytes are located in the central nervous system and can myelinate multiple axons simultaneously. This difference reflects their unique roles in supporting neuronal function within their respective systems.
• Evaluate the impact of Schwann cell dysfunction on nerve health and potential therapeutic approaches to address such issues.
  • Dysfunction or damage to Schwann cells can lead to various neurological disorders characterized by impaired nerve conduction, such as Guillain-Barré syndrome or Charcot-Marie-Tooth disease. These conditions can result in symptoms like muscle weakness, sensory loss, or pain. Research into therapeutic approaches includes strategies to promote Schwann cell survival and function, as well as stem cell therapies aimed at regenerating damaged nerves. Understanding the mechanisms behind Schwann cell roles opens avenues for innovative treatments to restore nerve health and functionality.

Related terms

Myelin: A fatty substance that forms a protective sheath around the axons of neurons, facilitating faster signal transmission.

Node of Ranvier: Periodic gaps in the myelin sheath where ion exchange occurs, allowing for the rapid propagation of action potentials.

Oligodendrocytes: Glial cells in the central nervous system that also form myelin sheaths, but can myelinate multiple axons simultaneously.