( ( ( Alpha 2 ) ( adrenergic receptors ) ) ( ( are ( ( concentrated ( on ( ( ( precapillary arterioles ) and ) ( decrease ( mucosal ( capillary ( blood flow ) ) ) ) ) ) ) ( when activated ) ) ) . ) )
(ROOT (S (NP (ADJP (NNP Alpha) (CD 2)) (JJ adrenergic) (NNS receptors)) (VP (VBP are) (VP (VBN concentrated) (PP (IN on) (NP (NP (JJ precapillary) (NNS arterioles)) (CC and) (NP (NN decrease) (JJ mucosal) (JJ capillary) (NN blood) (NN flow)))) (SBAR (WHADVP (WRB when)) (S (VP (VBN activated)))))) (. .)))
Alpha 2 adrenergic receptors are concentrated on precapillary arterioles and decrease mucosal capillary blood flow when activated.
(ROOT (NP (NP (NP (DT The) (ADJP (RB precapillary) (JJ sphincters)) (NN regulate)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-))) (NP (NP (DT the) (NN passage)) (PP (IN of) (NP (NP (NN blood)) (PP (IN into) (NP (JJ capillary) (NNS beds)))))) (. .)))