Fig.: A diagram of a section of an alveolus with a pulmonary capillary
๐๐ซ๐๐๐๐ก๐๐ ๐ข๐ ๐๐๐ฆ๐๐ฆ
Alveoli are the primary sites of exchange of gases.
Gaseous Exchange in Lungs
โ At alveoli level, gaseous exchange occur through respiratory membrane (diffusion membrane) which is 0.2 mm thick (total thickness is much less than a mm).
โ ๐๐ ๐ฐ๐ผ๐ป๐๐ถ๐๐ ๐ผ๐ณ ๐๐ต๐ฟ๐ฒ๐ฒ ๐น๐ฎ๐๐ฒ๐ฟ๐:
(i) Alveolar epithelium (thin squamous epithelium)
(ii) Basement substance in between them (composed of a thin basement membrane supporting the squamous epithelium and the basement membrane surrounding the single layer endothelial cells of capillaries)
(iii) Endothelium of alveolar blood capillaries
โ Exchange of gases also occur between blood and tissues.
โ O2 and CO2 are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient
โ Pressure contributed by an individual gas in a mixture of gases is called partial pressure and is represented as pO2 for oxygen and pCO2 for carbon dioxide.
๐๐ซ๐๐๐๐ก๐๐ ๐ข๐ ๐๐๐ฆ๐๐ฆ
Alveoli are the primary sites of exchange of gases.
Gaseous Exchange in Lungs
โ At alveoli level, gaseous exchange occur through respiratory membrane (diffusion membrane) which is 0.2 mm thick (total thickness is much less than a mm).
โ ๐๐ ๐ฐ๐ผ๐ป๐๐ถ๐๐ ๐ผ๐ณ ๐๐ต๐ฟ๐ฒ๐ฒ ๐น๐ฎ๐๐ฒ๐ฟ๐:
(i) Alveolar epithelium (thin squamous epithelium)
(ii) Basement substance in between them (composed of a thin basement membrane supporting the squamous epithelium and the basement membrane surrounding the single layer endothelial cells of capillaries)
(iii) Endothelium of alveolar blood capillaries
โ Exchange of gases also occur between blood and tissues.
โ O2 and CO2 are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient
โ Pressure contributed by an individual gas in a mixture of gases is called partial pressure and is represented as pO2 for oxygen and pCO2 for carbon dioxide.