Pressure changes in the cardiac
cycle:
(a) During
the cardiac cycle the heart fills with blood and then the ventricles contract.
The table gives the filling time and the contraction time at different heart
rates.
|
Heart rate/beats
per minute |
Filling time/seconds
|
Contraction
time/seconds |
|
39.7
|
0.37
|
1.14
|
|
49.6
|
0.38
|
0.83
|
|
71.4
|
0.38
|
0.46
|
|
81.1
|
0.38
|
0.36
|
|
87.0
|
0.39
|
0.30
|
(i) Give
two conclusions that can be drawn from the figures in the table.
1
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2
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(2)
(ii) Explain
how you would use the figures in the table to calculate the contraction time at
a heart rate of 60 beats per minute.
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(2)
(iii) What
additional information would you need in order to find the cardiac output at a
particular heart rate?
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(1)
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