Asked by pranavjain | 1st Aug, 2010, 02:03: PM

Expert Answer:

Oxygen present in the alveolar air diffuses into the blood capillaries surrounding the alveoli. This is because the alveolar air is rich in oxygen whereas the blood in the capillaries is deficient in oxygen.
At the same time, carbondioxide from the blood diffuses into the alveoli since the blood surrounding the alveoli is rich in carbondioxide.
Thus the deoxygenated blood now becomes oxygenated and this oxygenated blood can be taken to the tissues for oxidation by the cells. Since purification of blood involves the removal of carbondioxide and addition of oxygen, the purification is called as gaseous exchange.

Answered by  | 2nd Aug, 2010, 07:30: AM

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