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Figure 2 shows a photograph of a dissected heart - AQA - A-Level Biology - Question 3 - 2019 - Paper 1
Question 3
Figure 2 shows a photograph of a dissected heart. **Figure 2** - Left atrium - Valve A - Chamber B 1. Name valve A and chamber B. **[1 mark]** Valve A ___... show full transcript
Worked Solution & Example Answer:Figure 2 shows a photograph of a dissected heart - AQA - A-Level Biology - Question 3 - 2019 - Paper 1
Step 1
Step 2
Give two safety precautions that should be followed when dissecting a heart.
Step 3
Explain how valve A in Figure 2 maintains a unidirectional flow of blood.
Answer
Valve A maintains a unidirectional flow of blood through the following mechanisms:
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When the pressure in the left atrium is higher than in the left ventricle, valve A opens to allow blood to flow from the atrium into the ventricle.
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Conversely, when the pressure in the left ventricle exceeds that in the left atrium, valve A closes to prevent any backflow of blood, thus ensuring that blood flows only in one direction during the cardiac cycle.