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1 Figure 1 shows the pathways in
the heart for the conduction of
electrical impulses during the cardiac cycle.
(a) Name structure A. (1 mark)
(b) Explain why each of the following is important in pumping blood through the heart.
(i) There is a short delay in the passage of impulses through part B.
(ii) The contraction of the ventricles starts at the base. (2 marks)
(c) The table shows the blood pressure in the left atrium, the left ventricle and the
aorta at different times during part of a cardiac cycle.
Blood pressure / kPa (i) At which time is
Time / s Left atrium Left ventricle Aorta blood flowing into
0.0 0.5 0.4 10.6 the aorta?
0.1 1.2 0.7 10.6 (ii) Between which
times are the
0.2 0.3 6.7 10.6
0.3 0.4 17.3 16.0 valves closed? (2 marks)
0.4 0.8 8.0 12.0
(d) The maximum pressure in the left ventricle is higher than the maximum pressure
in the right ventricle. What causes this difference in pressure? (1 mark)
2 Figure 2 shows the left side of the heart at two stages in a cardiac cycle.
(a) Name the structure
X labelled X. (1 mark)
(b) Describe two
pieces of evidence
in Diagram B
which indicate that
the ventricle is
emptying. (2 marks)
Figure 2 Diagram A Diagram B
(c) During exercise the rate of blood flow to heart muscle increases from 270 cm3 per
minute to 750 cm3 per minute.
(i) Calculate the percentage increase in rate of blood flow to heart muscle
during exercise. Show your working.
(ii) Explain the advantage of the increase in the rate of blood flow to heart
muscle during exercise. (4 marks)
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AQA Examination-style questions
3 (a) The times taken in the various stages of a complete cardiac cycle are shown in the table.
Stage of cardiac cycle Time taken / s
Contraction of the atria 0.1
Contraction of the ventricles 0.3
Relaxation of both atria and ventricles 0.4
(i) Use the information in the table to calculate the heart rate in beats per minute.…read more