BIOLOGY 5090 · STRUCTURED PRACTICE
1
(a)
[3]Identify structure P and valve Q. State the vital function of structure P in maintaining the efficiency of the mammalian circulatory system.
(b)
[3]With reference to blood pressure changes shown in the graph:
(i)
[2]Explain why valve Q closes at Point X.
(ii)
[1]Explain why the aortic semilunar valve opens at Point Y.
(c)
[5]Coronary heart disease (CHD) is a major cause of mortality worldwide.
(i)
[3]Describe how the narrowing of a coronary artery by an atheroma (fatty deposit) can lead to a myocardial infarction (heart attack).
(ii)
[2]State two dietary or lifestyle modifications that reduce the risk of coronary heart disease.
Total: 11 marks