Question

How does gaseous exchange take place at blood level?

Answer 1

1. Lungs are made up of several thousands of small chambers called alveoli.
2. Within the alveoli, an exchange of gases takes place between the gases inside the alveoli and blood.
3. Blood arriving in the alveoli has a higher CO₂ concentration which is produced during respiration by the body cells.
4. At the same time air in the alveoli has a much lower concentration of CO₂ and this allows the diffusion of CO₂ out of the blood and to alveolar air.
5. Similarly blood arriving in the alveoli has a lower oxygen concentration while the air in the alveoli has a higher oxygen concentration.
6. Therefore oxygen moves into the blood by diffusion.