pls explain about the exchange of gases in alveoli and blood tissues
- Alveoli are microscopic air sacs. They are the primary sites of exchange of gases. Gas exchange also occurs in lungs and tissues by diffusion.
- Atmospheric air contains little CO2, but blood flowing in pulmonary capillaries has a higher concentration of CO2.
- CO2 diffuses from higher concentration in blood across walls of alveolar capillaries to lower concentration in air in alveoli.
- Blood coming into pulmonary capillaries is oxygen poor and alveolar air is oxygen rich.
- Oxygen diffuses from higher concentration in alveoli across walls of alveolar capillaries to lower concentration in blood.