Podcast
Questions and Answers
What is the primary role of Schwann cells in the peripheral nervous system?
What is the primary role of Schwann cells in the peripheral nervous system?
What is formed at the gaps between the segments of the myelin sheath?
What is formed at the gaps between the segments of the myelin sheath?
Which cellular structure is responsible for myelinating multiple axons in the central nervous system?
Which cellular structure is responsible for myelinating multiple axons in the central nervous system?
How do Schwann cells contribute to peripheral nerve regeneration after injury?
How do Schwann cells contribute to peripheral nerve regeneration after injury?
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Which of the following correctly describes non-myelinating Schwann cells?
Which of the following correctly describes non-myelinating Schwann cells?
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What condition can specifically affect Schwann cells, leading to muscle weakness?
What condition can specifically affect Schwann cells, leading to muscle weakness?
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Which of the following roles do Schwann cells NOT perform?
Which of the following roles do Schwann cells NOT perform?
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What effect does myelination have on nerve impulse transmission?
What effect does myelination have on nerve impulse transmission?
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Study Notes
Structure and Function
- Schwann cells are glial cells in the peripheral nervous system (PNS).
- They myelinate axons, increasing nerve impulse speed.
- Myelin is a fatty substance forming an insulating sheath around the axon.
- The myelin sheath is segmented by Schwann cell membranes.
- Gaps between segments are Nodes of Ranvier.
- Saltatory conduction occurs at the nodes, where action potentials jump between nodes, speeding transmission.
- Schwann cells support and nourish myelinated axons.
Myelination Process
- Schwann cells wrap around the axon in a spiral.
- Cytoplasm and nucleus of the Schwann cell are pushed to the periphery during wrapping.
- Tight packing of the cell membrane forms the myelin sheath.
Types of Schwann Cells:
- Myelinating Schwann cells form myelin sheaths around large-diameter axons; the most common type.
- Non-myelinating Schwann cells support and surround small, unmyelinated axons, also known as supporting cells (or satellite cells). They lack the tight layering of myelinating Schwann cells.
PNS vs. CNS
- Schwann cells myelinate axons in the peripheral nervous system (PNS).
- Oligodendrocytes myelinate axons in the central nervous system (CNS).
- Oligodendrocytes can myelinate multiple axons, while Schwann cells myelinate only one.
Regeneration
- Schwann cells are crucial for peripheral nerve regeneration after injury.
- They form a regeneration tube guiding growing axons to their target.
- Schwann cells are essential for successful regeneration in the PNS.
Functions Beyond Myelination
- Schwann cells have support roles beyond myelination.
- They influence synaptic transmission rates by regulating neurotransmitter release and uptake.
- They maintain the chemical balance of the extracellular environment around neurons.
- They are involved in PNS development and maintenance.
Diseases Affecting Schwann Cells
- Guillain-Barré syndrome targets Schwann cells; an autoimmune disease.
- Demyelination of peripheral nerves in Guillain-Barré leads to muscle weakness and paralysis.
- Hereditary neuropathies can also affect Schwann cell function.
Other Key Details
- Schwann cells maintain the structural integrity of peripheral nerves.
- Their function is critical for signal transmission throughout the body.
- Their role in nerve regeneration highlights their importance for recovery after nerve damage.
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Description
This quiz covers the structure, function, and myelination process of Schwann cells in the peripheral nervous system. Learn about their role in nerve impulse transmission and the features of the myelin sheath. Test your understanding of key concepts like saltatory conduction and Types of Schwann Cells.
