Sets of hystereses (lung volume versus intrapleural pressure) for three breathing frequencies. a) The normal (solid curves) and the increased (dotted curves) Raw; FRC – functional residual capacity, RC – residual capacity, which is greater than FRC in the case of the increased Raw because the lungs have too small time to empty themselves to the FRC level through the increased Raw. Therefore, if Raw is increased, then VT depends on the breathing frequency. Note that the end-inspiratory volume is almost independent from the frequency. b) Raw = 8·norm, without (dotted curves) and with the support (solid curves).