Describe the function of alveoli.
- OCR - GCSE Physical Education - Question 1 - 2018 - Paper 1
Question 1
Describe the function of alveoli.
Worked Solution & Example Answer:Describe the function of alveoli.
- OCR - GCSE Physical Education - Question 1 - 2018 - Paper 1
Step 1
Allows gaseous exchange/diffusion.
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Answer
Alveoli are tiny air sacs in the lungs that facilitate the exchange of gases. They provide a large surface area to maximize the amount of oxygen that can diffuse into the blood and carbon dioxide that can be expelled from the blood.
Step 2
Allows oxygen to diffuse/move into the blood/capillaries.
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Answer
When air enters the alveoli, oxygen diffuses across the alveolar membrane into the surrounding capillaries, where it binds to hemoglobin in red blood cells for transport throughout the body.
Step 3
Allows carbon dioxide to diffuse/move from the blood/capillaries.
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Answer
Simultaneously, carbon dioxide in the blood diffuses from the capillaries into the alveoli, from where it is expelled during exhalation, maintaining the body's acid-base balance.
