A brain scan shows the result of a small stroke in a 68-year-old patient. The blockage reduced blood flow to area P. Doctors asked the patient to squeeze ea...
Question 1 Report
A brain scan shows the result of a small stroke in a 68-year-old patient. The blockage reduced blood flow to area P. Doctors asked the patient to squeeze each hand, speak a short sentence and identify objects placed in the left hand. Fig. 1 is a simplified side view of the brain. The cerebrum receives sensory information and controls many voluntary actions. The brain stem controls automatic functions such as breathing. The patient’s blood glucose and oxygen concentration were normal when the tests were carried out.
(a) Which major region of the brain contains area P? [2]
(b) Suggest why a blockage in a blood vessel can damage brain cells. [2]
(c) Describe one test the doctors could use to check voluntary control of the patient’s left hand. [2]
(d) What is the advantage of using a brain scan as well as observing the patient’s symptoms? [2]
Answer Details
(a) Area P is in the cerebrum [1]. Cerebral cortex is also acceptable [1].
(b) A blockage reduces the blood supply, so brain cells receive less oxygen or glucose [1]. Aerobic respiration releases less energy, so cells cannot function normally and may die [1].
(c) Ask the patient to squeeze a hand, lift fingers or pick up an object [1]. Compare movement, strength or accuracy with the right hand [1]. This gives a direct comparison of voluntary control on the two sides.
(d) A brain scan locates the damaged area [1]. This allows symptoms to be linked to a particular brain region, helping diagnosis and treatment [1].
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