Neurilemma vs Myelin Sheath: Key Differences Explained
Neurilemma is the outermost layer of Schwann cells that encloses peripheral nerve fibers; the myelin sheath is the fatty insulation wrapped around those same fibers inside the neurilemma.
Students mix them because both surround axons and both appear in the same textbook diagrams, so “the outer thing” and “the white stuff” blur together in memory.
Key Differences
Neurilemma contains the Schwann-cell cytoplasm and nucleus, enabling regeneration after injury. Myelin is concentric lipid layers that speed electrical impulses; it lacks living cytoplasm and cannot regrow once lost.
Which One Should You Choose?
When discussing nerve repair or peripheral neuropathy, emphasize the neurilemma’s role. For topics like multiple sclerosis or signal velocity, focus on the myelin sheath.
Examples and Daily Life
A skin cut that severs a finger nerve heals well thanks to the neurilemma guiding regrowth. In contrast, MS symptoms worsen when immune attacks strip away myelin and slow brain-to-body signals.
Does the brain use neurilemma?
No; oligodendrocytes create myelin in the CNS, leaving neurilemma exclusive to peripheral nerves.
Can myelin regrow?
Peripheral myelin can remyelinate slowly if the neurilemma survives, but central myelin regrowth is limited and often incomplete.