Figure 5 shows the estimated blood flow through some parts of the body when a person is at rest and during exercise - Edexcel - GCSE Biology Combined Science - Question 3 - 2018 - Paper 1
Question 3
Figure 5 shows the estimated blood flow through some parts of the body when a person is at rest and during exercise.
| part of the body | estimated r... show full transcript
Worked Solution & Example Answer:Figure 5 shows the estimated blood flow through some parts of the body when a person is at rest and during exercise - Edexcel - GCSE Biology Combined Science - Question 3 - 2018 - Paper 1
Step 1
Compare the rate of blood flow through the body when this person is at rest and during exercise.
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Answer
The rate of blood flow through the brain and other organs stays the same, with the brain receiving 750 cm³ per minute at rest, which decreases slightly to 748 cm³ per minute during exercise. In contrast, blood flow to the heart muscle significantly increases from 350 cm³ per minute at rest to 1,150 cm³ per minute during exercise. Additionally, blood flow to the digestive system decreases from 2,500 cm³ per minute at rest to 1,200 cm³ per minute during exercise, indicating a shift that prioritizes blood flow to active muscles.
Step 2
From which chamber of the heart does this volume of oxygenated blood flow?
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Answer
B left ventricle
Step 3
Calculate the heart rate.
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Answer
To calculate the heart rate, we use the formula:
Heart Rate=Stroke VolumeCardiac Output
Given that the cardiac output is 4.9 litres per minute (or 4900 ml) and the stroke volume is 70 ml, we can substitute these values into the formula:
