Question
The figure given below shows a small part of human lung where exchange of gases takes place. In which one of the options given below, the one part A, B, C or D is correctly identified along with its function.
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A: Alveolar cavity - main site of exchange of respiratory gases
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D: Capillary wall - exchange of O2 and CO2 takes place here
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B : Red blood cell - transport of CO2 mainly
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C : Arterial capillary - passes oxygen to tissues
Solution
A.
A: Alveolar cavity - main site of exchange of respiratory gases
Alveoli are the primary sites of exchange of gases. The exchange of gases (O2 and CO2) between the alveoli and the blood occurs by simple diffusion.
