<prompt> Normal respiratory compliance is ?200 mlcm water50 mlcm water100 mlcm water150 mlcm water  <response>: The lungs and thoracic cage are both elastic structures. Hence they display a constant relationship between distending pressure and change in volume. The change in volume per unit change in pressure is called compliance. The total compliance of both lungs together in the normal adult human being is about 0.2 Lcm water. That is, every time the transpulmonary pressure increases by 1 centimeter of water, the lung volume will expand 0.2 L 200 ml. Compliance is a measure of distensibility. Ref: Guyton 12th Ed. 