To understand how the input impedance determined at the throat correlates with changes in the dynamic characteristics of the airways, a simplified 5-lobe model is developed and simulated. The model takes into account some realistic conditions such as varying cross-sectional areas, flexible wall properties and branching. The lobe terminal impedances are implemented in the model to predict the input impedance at the throat. The effects of airway constrictions and wall elastance variations on this impedance are determined for a range of frequencies. It is concluded that the developed model is capable of predicting various physiological changes in the airway passages.