Question

EXPLAIN ventilation perfusion ratio

Answer 1

Ventilation (V) is the amount of air entry to that particular lung region and the perfusion (Q) is the amount of blood supply to that lung region.

The V and Q are not equal through out the lung. This V/Q ratio can be made use to know the efficiency of gaseous exchange in the lungs.

So for ideal conditions, V/Q should be 1 means that both ventilation and perfusion must be equal. But in lungs, the blood supply is more compared to air entry so it is normally around 0.8

Also the base of the lung has more blood supply (due to gravity affect on blood) and the air entry is higher at the lung apex (as air is lighter in weight). Thses factors also tend to change the V/Q ratio.

Hope this helps... Thank you!!!