Explain the process of exchange of gases with the help of a diagrammatic representation of the human respiratory system.

Open in App

Solution

Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues.
O $_{2}$ and CO $_{2}$ are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient.
The solubility of the gases, as well as the thickness of the membranes involved in diffusion, are also some important factors that can affect the rate of diffusion.
Pressure contributed by an individual gas in a mixture of gases is
called partial pressure and is represented as pO $_{2}$ for oxygen and pCO $_{2}$ for carbon dioxide.
a gradient is present for CO $_{2}$ in the opposite
direction, i.e., from tissues to blood and
blood to alveoli. As the solubility of CO $_{2}$ is
20-25 times higher than that of O $_{2}$ the
amount of CO $_{2}$ that can diffuse through the
diffusion membrane per unit difference in
partial pressure is much higher compared
to that of O $_{2}$ .
The diffusion membrane is
made up of three major layers
namely, the thin squamous epithelium of
alveoli, the endothelium of alveolar capillaries
and the basement substance in between
them. However, its total thickness is much
less than a millimetre. Therefore, all the
factors in our body are favourable for
diffusion of O $_{2}$ from alveoli to tissues and that
of CO $_{2}$ from tissues to alveoli.

Suggest Corrections

Similar questions

Where does the exchange of gases take place in the respiratory system?

Join BYJU'S Learning Program