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Exercise causes changes in the circulation of the blood - Edexcel - GCSE Biology Combined Science - Question 6 - 2021 - Paper 1
Question 6
Exercise causes changes in the circulation of the blood. In an investigation, the change in blood flow to different parts of the body during exercise was measured. A... show full transcript
Worked Solution & Example Answer:Exercise causes changes in the circulation of the blood - Edexcel - GCSE Biology Combined Science - Question 6 - 2021 - Paper 1
Step 1
During exercise, the blood flow to the stomach changes. Calculate the percentage change in blood flow to the stomach in response to exercise.
Answer
To calculate the percentage change in blood flow to the stomach, we first look at the values from Figure 9. At rest, the blood flow to the stomach is 800 cm³ per minute, while during exercise, it is 200 cm³ per minute.
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Calculate the change in blood flow:
Change in blood flow = Blood flow at rest - Blood flow during exercise = 800 cm³ - 200 cm³ = 600 cm³.
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Calculate the percentage change:
Percentage change = (Change / Blood flow at rest) * 100 = (600 cm³ / 800 cm³) * 100 = 75%.
Thus, the percentage change in blood flow to the stomach in response to exercise is 75%.
Step 2
Step 3
Explain the changes in blood flow, shown in Figure 9, that are caused by exercise.
Answer
Exercise causes various physiological changes that affect blood flow:
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Increased heart rate: Exercise stimulates the heart to pump more blood to meet the increased oxygen demand of the muscles.
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Increased blood flow to working muscles: Blood flow increases to the muscles that are actively engaged in exercise, aiding in delivery of oxygen and glucose, and removal of metabolic waste such as carbon dioxide and lactic acid.
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Decreased blood flow to non-essential organs: Blood flow to the stomach and kidneys decreases during exercise as the body prioritizes blood flow to the heart and muscles. This is necessary to allocate resources effectively.
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Constant blood flow to the brain: Blood flow to the brain remains unchanged to ensure a constant supply of oxygen and glucose, which are essential for maintaining cognitive and motor functions.
Overall, exercise leads to an adaptive increase in blood flow to active muscle tissues while reducing flow to non-critical areas.