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The diagram shows a section through a kidney - OCR Gateway - GCSE Biology - Question 18 - 2023 - Paper 1
Question 18
The diagram shows a section through a kidney. (i) Name the region labelled A. (ii) Name the region labelled B. (iii) Which type of blood vessel brings blood to th... show full transcript
Worked Solution & Example Answer:The diagram shows a section through a kidney - OCR Gateway - GCSE Biology - Question 18 - 2023 - Paper 1
Step 1
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Step 4
Calculate the volume of urine that will be produced by this person on this day.
Answer
To calculate the volume of urine produced, we first find the total water gained and lost:
Total water gained = 2.2 (food and drink) + 0.3 (metabolic processes) = 2.5 litres.
Total water lost = 0.9 (from skin and lungs) + 0.1 (faeces) + volume of urine.
Using the balance: 2.5 = 0.9 + 0.1 + volume of urine.
This simplifies to: volume of urine = 2.5 - 1 = 1.5 litres.
Step 5
Explain how the kidney will maintain the water balance within this person’s body during the race.
Answer
During the marathon race, the body's water balance is crucial. The kidneys will respond to increased physical activity by regulating water reabsorption.
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Antidiuretic Hormone (ADH): The body may release more ADH in response to dehydration, which encourages the kidneys to reabsorb more water and produce less urine.
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Maintaining Blood Pressure: As the person sweats during the race, blood volume may decrease. The kidneys help regulate this by adjusting urine output to preserve fluid balance.
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Filtration Rate Adjustment: The kidneys can alter the glomerular filtration rate based on hydration levels.
Thus, the kidneys play a vital role in ensuring that the athlete remains hydrated and maintains homeostasis during prolonged physical exertion.