Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why? |NCERT solution|Class 11 Biology|Unit-17 Breathing and exchange of gases



Q.3:- Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?

 

Answer:



The exchange part of the respiratory system is composed of the alveoli and their ducts. Actual diffusion of O2 and CO2 (between blood and atmospheric air) takes place in the exchange part of the respiratory system. The thin membrane of the alveoli is suited for diffusion of gases, while other parts of the respiratory system are not structured to serve this purpose. Hence, diffusion of gases takes place in the alveolar region only and not in the other parts of the respiratory system.