... generations (A, black line), away from regions of branching; (Analysis 2), narrowing in the parent bronchus wasmeasured at the midpoint of branching, where the parent bronchuswas seen to open into ... in pig bronchi in vitro in which airwaynarrowing was measured endoscopically in separatelarge and small diameter airways [7]. The present studyextends these findings by documenting narrowing ... hyperinflation, an increa sed work of breathing and an impaired gas exchange, all of whichocc ur in obstructiv e respiratory disease (asthma) . Whileairway closure was not observed in this study, it isimportant...