Question

Explain the schematic representation of gaseous exchange in tissues?

Answer 1

Gaseous exchange: It is referred to as the exchange of gases at tissue level between carbon dioxide and oxygen. The oxygen is made available to the cells whereas carbon dioxide is expelled out.

Exchange of gases in the tissues:

1. The alveoli in the lungs are the primary site for the exchange of gases but the exchange of gasses also occurs between the blood and the tissues. O₂ and CO₂ exchange occur through simple diffusion due to differences in partial pressure.
2. The pO₂ in the capillaries is 95 whereas pCO₂ is 40 but in the case of tissue, pO₂ is 40 and pCO₂ is 45. So we see there is a difference in the partial pressure of oxygen and carbon dioxide both in tissues and capillaries there will be an exchange of gases by simple diffusion.
3. We know that the gases travel from higher partial pressure to lower partial pressure, so there will be the transport of oxygen from the capillaries to the tissue(pO₂ 95 ⇢pO₂ 40). Similarly, Carbon dioxide will also travel from the tissues to the capillaries(pCO₂ 45⇢pCO₂ 40).

Hence this is how the exchange of gases takes place in the tissues.