k Resistance to breathing Elastic of the lung Elastic compliance I/RL=△VL△Pu(L/cmH2O) Static compliance(Cst) of the lung S shaped curve, divided into 3 portions Flattened upper portion Steep middle portion Flattened lower portion Special compliance( C= CU/TLC* Resistance to breathing Elastic ~ of the lung Elastic ~ & Compliance CL=1/RL=VL/PL(L/cmH2O) Static compliance (Cst) of the lung S shaped curve, divided into 3 portions Flattened upper portion Steep middle portion Flattened lower portion Special compliance (Csp) Csp = CL/TLC