( ( Vasoconstriction ( -LRB- ( ( ( ( vessel narrowing ) or ) constricting ) -RRB- ) ) ) ( ( is ( ( a decrease ) ( in ( ( blood ( vessel diameter ) ) ( that ( will ( lead ( to ( ( a decrease ) ( in ( blood flow ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Vasoconstriction)) (PRN (-LRB- -LRB-) (NP (NP (NN vessel) (NN narrowing)) (CC or) (NP (NNP constricting))) (-RRB- -RRB-))) (VP (VBZ is) (NP (NP (DT a) (NN decrease)) (PP (IN in) (NP (NP (NN blood) (NN vessel) (NN diameter)) (SBAR (WHNP (WDT that)) (S (VP (MD will) (VP (VB lead) (PP (TO to) (NP (NP (DT a) (NN decrease)) (PP (IN in) (NP (NN blood) (NN flow))))))))))))) (. .)))
Vasoconstriction (vessel narrowing or constricting) is a decrease in blood vessel diameter that will lead to a decrease in blood flow .
(ROOT (S (NP (NNP Blood)) (VP (VBP flow) (VP (VB decrease) (SBAR (WHADVP (WRB when)) (S (NP (NN blood) (NNS vessels)) (VP (VBP constrict)))))) (. .)))