Question

Plz explain it...........

Answer 1

Partial pressure is the pressure exerted by a gas in a mixture of gases.

Partial pressure of oxygen is maximum in alveolar air with respect to rest of the bdy parts.

Since partial pressure of O2 is more in alveoli and less in arteries (with respect to) so O2 diffuses from alveoli into arteries. Now this oxygenated arterial blood has more partial pressure of O2 than cells of the body so O2 diffuses from these arteries and enters into cells where it is utilised for various metabolic activities.

Now cells have more lartial lressure of CO2 with respect to blood so CO2 now diffuses from cells to blood and now the blood i.e.venous blood or deoxygenated blood has more partial pressure of CO2 than alveoli so this CO2 diffuese from blood to alveoli . Now partial pressure of CO2 is more in alveoli than atmosphere so expiration takes place to remove CO2 from the body so partial pressure of CO2A will be more in expired air.

So answer is a) alveolar air