[Diagram: B&W exam-style line-art schematic on white: football goalkeeper lower leg nervous pathway, receptor in foot connected by sensory neurone to spinal...
Question 1 Report
[Diagram: B&W exam-style line-art schematic on white: football goalkeeper lower leg nervous pathway, receptor in foot connected by sensory neurone to spinal cord and brain, motor neurone from spinal cord to cal]
Fig. 1 shows a simplified pathway controlling movement of the lower leg when a football goalkeeper kicks a ball. A scan later showed damage to the insulating layer around some neurones in the player's leg. The player could still detect touch but the leg muscle contracted slowly.
(a) Name the type of neurone carrying impulses from the spinal cord to the leg muscle. [1]
(b) Describe the direction of travel of an impulse from the receptor in the foot to the brain. [2]
(c) Complete the sequence for a reflex arc by writing the missing terms.
receptor → sensory neurone → ............ → motor neurone → effector [2]
(d) Explain how damage to the insulating layer can reduce the speed of movement of the leg. [5]
Answer Details
(a) The neurone carrying impulses from the spinal cord to the leg muscle is a motor neurone. [1]
(b) The impulse travels from the foot receptor along a sensory neurone to the spinal cord. It then travels through neurones to the brain. [2]
(c) The completed sequence is:
receptor → sensory neurone → relay neurone → motor neurone → effector
The relay neurone is in the spinal cord, which is part of the central nervous system. [2]
(d) The insulating layer normally prevents electrical signal loss and increases the speed of impulse conduction. Damage to it slows impulses along the neurone. Motor impulses then arrive at the leg muscle later, so the muscle contracts later and movement or reaction when kicking is slower. [5]
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