Fig. 1 shows a doctor tapping below a patient's kneecap during a routine examination. A lower-leg muscle contracts and the foot moves forwards. The doctor u...
Question 1 Report
Fig. 1 shows a doctor tapping below a patient's kneecap during a routine examination. A lower-leg muscle contracts and the foot moves forwards. The doctor uses this response to check that sensory and motor neurones are working. The movement happens without a decision by the patient.
(a) Identify the type of response tested by the doctor. [1]
(b) Use the figure to describe the role of a sensory neurone in this response. [2]
(c) Explain why this response is useful when the leg is suddenly stretched. [2]
Answer Details
(a) Reflex action [1] (b) It carries impulses from a stretch receptor / receptor in muscle [1]; to the spinal cord / central nervous system [1] (c) The muscle contracts quickly [1]; this prevents excessive stretch and possible damage / helps maintain posture [1]
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