key term - Schwann Cells

Definition

Schwann cells are a type of glial cell found in the peripheral nervous system. They are responsible for forming the myelin sheath around the axons of neurons, which enhances the speed of electrical signal transmission. Schwann cells are essential for the proper function and maintenance of the peripheral nervous system.

5 Must Know Facts For Your Next Test

1. Schwann cells produce the myelin sheath, which acts as an insulator around the axons of peripheral neurons, increasing the speed of electrical signal transmission.
2. Schwann cells also provide physical support and protection for peripheral neurons, and they play a crucial role in the regeneration of damaged nerves.
3. In the PNS, Schwann cells are responsible for the myelination of motor and sensory neurons, which is essential for the proper functioning of the nervous system.
4. Schwann cells are derived from the neural crest, a transient embryonic structure that gives rise to various cell types, including neurons and glial cells.
5. Disruption or dysfunction of Schwann cells can lead to peripheral neuropathies, such as Charcot-Marie-Tooth disease, where the myelin sheath is damaged or absent.

Review Questions

• Explain the role of Schwann cells in the structure and function of the peripheral nervous system.
  • Schwann cells are essential for the proper functioning of the peripheral nervous system. They form the myelin sheath around the axons of peripheral neurons, which increases the speed of electrical signal transmission. The myelin sheath acts as an insulator, allowing for faster and more efficient communication between the central nervous system and the rest of the body. Additionally, Schwann cells provide physical support and protection for peripheral neurons, and they play a crucial role in the regeneration of damaged nerves.
• Describe the developmental origin and differentiation of Schwann cells.
  • Schwann cells are derived from the neural crest, a transient embryonic structure that gives rise to various cell types, including neurons and glial cells. During development, neural crest cells migrate and differentiate into Schwann cell precursors, which then mature into Schwann cells. The differentiation of Schwann cells is regulated by a complex interplay of transcription factors and signaling pathways, ensuring the proper formation and function of the myelin sheath around peripheral neurons.
• Analyze the potential implications of Schwann cell dysfunction or disruption in the context of peripheral nervous system disorders.
  • Disruption or dysfunction of Schwann cells can lead to various peripheral neuropathies, such as Charcot-Marie-Tooth disease. In these disorders, the myelin sheath around peripheral neurons is damaged or absent, which impairs the speed and efficiency of electrical signal transmission. This can result in symptoms like muscle weakness, sensory loss, and impaired motor coordination. Understanding the critical role of Schwann cells in maintaining the structure and function of the peripheral nervous system is essential for developing effective treatments and interventions for peripheral nerve disorders.

Related terms

Myelin Sheath:

The lipid-rich insulating layer formed by Schwann cells around the axons of peripheral neurons, which increases the speed of electrical signal propagation.

Glial Cells:

Non-neuronal cells in the nervous system that provide support and protection for neurons, including Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.

Peripheral Nervous System (PNS): The part of the nervous system that connects the central nervous system (brain and spinal cord) to the rest of the body, including sensory receptors and effector organs.