( ( A ( precapillary sphincter ) ) ( ( is ( ( ( a band ) ( of ( smooth muscle ) ) ) ( that ( ( ( ( adjusts ( blood flow ) ) ( into capillaries ) ) mainly ) ( in ( the ( mesenteric microcirculation ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ precapillary) (NN sphincter)) (VP (VBZ is) (NP (NP (DT a) (NN band)) (PP (IN of) (NP (JJ smooth) (NN muscle))) (SBAR (WHNP (WDT that)) (S (VP (VBZ adjusts) (NP (NN blood) (NN flow)) (PP (IN into) (NP (NNS capillaries))) (ADVP (RB mainly)) (PP (IN in) (NP (DT the) (JJ mesenteric) (NN microcirculation)))))))) (. .)))
A precapillary sphincter is a band of smooth muscle that adjusts blood flow into capillaries mainly in the mesenteric microcirculation.
(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)))))) (. .)))