Fig. 1 shows a simplified section through the surface of a human heart. A cardiologist has identified a narrowed coronary artery at P in a person who experi...
Question 1 Report
Fig. 1 shows a simplified section through the surface of a human heart. A cardiologist has identified a narrowed coronary artery at P in a person who experiences chest pain when walking uphill.
(a) Name the type of blood vessel at P. [1]
(b) Describe how narrowing at P affects the blood supply to nearby heart muscle cells. [3]
(c) Explain how inserting a stent at P can reduce the person's symptoms. [2]
(d) Use the information in the question to explain why the chest pain is more likely during uphill walking than when resting. [2]
Answer Details
(a) P is an artery, specifically a coronary artery. [1]
(b) Narrowing reduces the amount of blood that can flow through the coronary artery. Consequently, less oxygen reaches nearby heart muscle cells. Less aerobic respiration can occur, so less energy is released for heart muscle contraction. [3]
(c) A stent holds the artery open and widens its lumen. This allows more blood, and therefore more oxygen, to reach the heart muscle, reducing symptoms caused by limited oxygen supply. [2]
(d) Uphill walking makes the heart work harder. Its muscle needs more oxygen, but the narrowed artery cannot provide enough blood and oxygen to meet the increased demand, causing chest pain. [2]
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