Influence of the working point on the differential lungs compliance. V – lungs volume, Pw – the difference between intrapleural and upper airways pressures, which is equal to the transpulmonary pressure when the air flow is equal to zero (thus, the broken line presents the nonlinear lungs compliance). The greater the lungs volume, the smaller the lungs volume increase (ΔV) caused by a particular pressure increase (Δp), i.e. the greater the volume, the smaller the differential compliance ΔV/Δp. Solid curves (hystereses) illustrate influence of Raw on the relationship between the volume and pressure during breathing with different deepness of breaths.