The diagram shows three neurones from an engineering project making a prosthetic hand. The team wants to copy the speed of a motor neurone that carries impu...
Question 1 Report
The diagram shows three neurones from an engineering project making a prosthetic hand. The team wants to copy the speed of a motor neurone that carries impulses from the spinal cord to a hand muscle. Some neurones have a fatty myelin sheath around the axon.
(a) Complete the description of the direction of an impulse in the neurone: cell body, ______, neurone ending. [1]
(b) Complete the statement: myelin increases the ______ of nerve impulse transmission. [2]
(c) Explain how a faster impulse along a motor neurone could improve the response of a prosthetic hand. [3]
(d) Design a fair investigation to compare impulse speed in model axons with and without an insulating sheath. [4]
Answer Details
(a) The route is cell body, axon, neurone ending. [1]
(b) Myelin increases the speed, or rate, of nerve impulse transmission. [2]
(c) Faster impulses reach the hand mechanism sooner. The hand begins moving with less delay, giving a quicker response to a stimulus and improved control. [3]
(d) Use two model axons of equal length and give each the same electrical input. Fit an identical insulating sheath to only one model. Measure the time taken for each signal to reach the end, then calculate speed using \(\text{speed}=\frac{\text{distance}}{\text{time}}\). Repeat trials, calculate means, and keep temperature constant. [4]
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