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Figure 10 shows alveoli from a lung - Edexcel - GCSE Biology - Question 9 - 2019 - Paper 1
Question 9
Figure 10 shows alveoli from a lung. Explain why these alveoli have the internal structure shown in Figure 10. (3) How does oxygen move across the alveolar membran... show full transcript
Worked Solution & Example Answer:Figure 10 shows alveoli from a lung - Edexcel - GCSE Biology - Question 9 - 2019 - Paper 1
Step 1
Explain why these alveoli have the internal structure shown in Figure 10.
Answer
The alveoli have a specialized internal structure to maximize the efficiency of gas exchange. Firstly, they are composed of a thin single layer of epithelial cells, which reduces the distance for diffusion of gases. Secondly, the large surface area is created by the numerous alveoli, facilitating more oxygen to enter the blood efficiently. Lastly, the presence of capillaries surrounding the alveoli ensures a constant blood flow, maintaining a concentration gradient that is essential for effective gas exchange.
Step 2