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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. ... 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, follow these steps:
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Identify the blood flow to the stomach at rest and during exercise. From Figure 9, we can assume the values are:
- Blood flow at rest = 800 cm³/min
- Blood flow during exercise = 1200 cm³/min
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Calculate the change in blood flow:
Change = Blood flow during exercise - Blood flow at rest = 1200 - 800 = 400 cm³/min
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Now, calculate the percentage change:
Percentage Change = (Change / Blood flow at rest) * 100 = (400 / 800) * 100 = 50%
Thus, the percentage change in blood flow to the stomach in response to exercise is 50%.
Step 2
Step 3
Explain the changes in blood flow, shown in Figure 9, that are caused by exercise.
Answer
During exercise, the blood flow changes considerably due to the body's increased demand for oxygen and nutrients.
Increased Blood Flow:
- Blood flow to the heart muscle increases to pump more blood.
- There is an increase in blood flow to other muscles to deliver more oxygen and glucose for energy production.
- Increased respiration rate occurs to enhance oxygen uptake and carbon dioxide removal.
- Blood flow to the skin may also increase to help cool the body through perspiration.
Decreased Blood Flow:
- Blood flow to the kidneys and stomach decreases during exercise, allowing more blood to flow towards the working muscles.
Constant Blood Flow:
- Blood flow to the brain remains constant as it requires a steady supply of oxygen and glucose to function properly.