Figure 1 shows a human heart - AQA - GCSE Biology Combined Science - Question 1 - 2019 - Paper 1
Question 1
Figure 1 shows a human heart.
0.1.1 Which blood vessel carries deoxygenated blood away from the heart to the lungs?
Tick (✓) one box.
A
B
C
D
0.1.2 The natural re... show full transcript
Worked Solution & Example Answer:Figure 1 shows a human heart - AQA - GCSE Biology Combined Science - Question 1 - 2019 - Paper 1
Step 1
0.1.1 Which blood vessel carries deoxygenated blood away from the heart to the lungs?
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Answer
The correct answer is B. The blood vessel that carries deoxygenated blood away from the heart to the lungs is the pulmonary artery.
Step 2
0.1.2 Where in the heart are 'pacemaker cells' found?
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Answer
Pacemaker cells are found in the right atrium. The sinoatrial node, which is responsible for initiating the heartbeat, is located here.
Step 3
0.1.3 Where does the drug digitalis originate from?
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Answer
Digitalis originates from foxgloves. This plant has been used historically in medicine to treat heart conditions.
Step 4
0.1.4 Calculate stroke volume X in Table 1.
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Answer
To find stroke volume X, use the equation: cardiac output = stroke volume × heart rate.
Given: cardiac output = 2800 cm³ per minute and heart rate = 52 beats per minute, we can rearrange the equation to find stroke volume:
X=522800≈53.846153.
Rounding to 2 significant figures, stroke volume X is 54 cm³.
Step 5
0.1.5 Explain why beta blockers can have this effect during exercise.
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Answer
Beta blockers reduce the heart rate during exercise, which in turn decreases stroke volume. This can lead to less cardiac output compared to individuals who do not take beta blockers. Because the body requires more oxygen during exercise, a reduced cardiac output means that less oxygen reaches the muscles, leading to breathlessness. Additionally, the heart's ability to respond to the increased demand for oxygen during physical activity may be impaired, further contributing to feelings of breathlessness.
