The Power Course

Upright position ventilation and perfusion of lungs


1 ) Ventilation is greater at base
2 ) Perfusion is a greater base
3 ) Ventilation-perfusion ratio decreases from apex to base
4 ) All of the above


In Upright position ventilation in more at base of the lungs than apex. This is because at the start of the inspiration apex is more distended compared to the base. Because of the stiffness of the lung, the increase in lung volume per unit increase in pressure is smaller when the lung is initially more expanded, and ventilation is consequently greater at the base

Blood flow is more at the base compared to apex

So the ventilation-perfusion ratio less at the base compared apex.


All of the above

Last Modified : 02-Jan-2020

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