Question

Which cells are the main sites of gas exchange?

Answer 1

Gas exchange:

1. Respiration is the mechanism by which living organisms take in oxygen and exhale carbon dioxide in order to obtain energy.
2. As a result, respiration is an essential and necessary mechanism of gas exchange.
3. The transport of gases during respiration, including oxygen and carbon dioxide, is done by blood cells.

Cells at the site of gaseous exchange: Alveoli in the lungs and blood capillaries.

1. The alveolus is the primary site of exchange as it has an extensive network of blood capillaries and consists of squamous epithelium.
2. Due to the very intimate contact of blood capillaries with the alveoli, the exchange of gases takes place easily.
3. Squamous epithelium of alveolar wall, endothelium of blood capillaries in alveoli and basement substance are the three layers forming diffusion surface or membrane.
4. This membrane allows the oxygen and carbon dioxide to diffuse freely between the respiratory system and the bloodstream.
5. This diffusion naturally occurs due to the partial pressure gradients of the respective gases.