How does gaseous exchange take place at blood level ?
A. ) Within the alveoli, exchange of gases takes place between the gases inside the alveoli and blood.
2) Blood arriving in the alveoli has a higher C02 concentration which is produced during respiration by the body’s cells.
3) At the same time air in the alveoli has a much lower concentration of C02 and this allows the diffusion of C02 out of the blood and to alveolar air.
4) Similarly blood arriving in the alveoli has a lower oxygen concentration while air in the alveoli has a higher oxygen concentration.
5) Therefore oxygen moves into the blood by diffusion.