A patient's myelin sheaths are progressively stripped from their nerves. What happens to their impulses?
AThey stop being generated at all
BThey travel much more quickly
CThey travel much more slowly
DThey reverse their direction of travel
Answer & Solution
Correct answer: C. They travel much more slowly
1. The myelin sheath wraps the nerve fibre and provides electrical insulation.
2. That insulation is what lets an impulse jump between gaps rather than creep along the whole membrane.
3. So myelin speeds up transmission along the nerve.
4. Stripping it away removes the speed advantage, and impulses travel far more slowly.
5. Impulses are still generated, and their direction is set by the neurone's structure, so neither of those changes.
_Source: NECTA ACSEE 2022 Biology 133/1, Question 3: Coordination_
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