( ( In PS ) ( , ( ( ( the ( smooth flow ) ) ( of ( blood ( into ( the lungs ) ) ) ) ) ( ( is obstructed ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NNP PS))) (, ,) (NP (NP (DT the) (JJ smooth) (NN flow)) (PP (IN of) (NP (NP (NN blood)) (PP (IN into) (NP (DT the) (NNS lungs)))))) (VP (VBZ is) (VP (VBN obstructed))) (. .)))
In PS, the smooth flow of blood into the lungs is obstructed.
(ROOT (S (NP (JJ Smooth) (NN muscle)) (VP (VBZ regulates) (NP (NP (NN air) (NN flow)) (PP (IN in) (NP (NNS lungs))))) (. .)))
Smooth muscle regulates air flow in lungs.