How does gaseous exchange take place in the alveoli?

Explanation

The primary site for the exchange of gases is the alveoli. The uptake of `O_(2)` and the release of `CO_(2)` occur between the blood and tissues by simple diffusion driven by partial pressure gradient of `O_(2)` and `CO_(2)` . Partial pressure is the pressure contributed by an individual gas in a mixture of gases . It is represented as `pO_(2)` for oxygen and `pCO_(2)` for carbon - dioxide . Due to pressure gradients , `O_(2)` from the alveoli enters into the blood and reaches the tissues . `CO_(2)` enters into the blood from the tissues and reaches alveoli for elimination . As the solubility of `CO_(2)` is 20-25 times higher than that of `O_(2)` , the partial pressure of `CO_(2)` is much higher than that of `O_(2)` .