A myelinated fibre conducts at 70 m/s. A thin non-myelinated fibre conducts at 1 m/s…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A myelinated fibre conducts at m/s. A thin non-myelinated fibre conducts at m/s. Each must carry a message m from the toe to the spinal cord.
- How long does the myelinated fibre take?
- How long does the non-myelinated fibre take?
- How many times faster is the myelinated fibre?
Need a reminder? The key ideaShow
Time equals distance divided by speed. A thin non-myelinated fibre conducts at about , and a thick myelinated fibre at about to . An electrical synapse passes current directly. A chemical synapse uses a neurotransmitter, and it adds a delay of about . The new potential may be excitatory or inhibitory.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Distance: m. Speeds: m/s and m/s.
Plan. Use for each fibre.
Step 1. Myelinated. s ms.
Step 2. Non-myelinated. s ms.
Step 3. The ratio. .
Answer: ms; ms; times.
Check. The ratio equals the ratio of the speeds, .
What if? With only non-myelinated fibres, a message from the toe would take more than a second. A runner could not react in time.
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