( ( As ( time ( goes ( by ( ( the veins ) ( ( ( become ( more ( and ( more tortuous ) ) ) ) , ) ( while ( ( ( the capillaries ) ( of ( the mucosa ) ) ) ( ( are gradually ) ( ( dilate and ) ( precapillary sphincter ) ) ) ) ) ) ) ) ) ) ) ( ( becomes incompetent ) . ) )
(ROOT (S (SBAR (IN As) (S (NP (NN time)) (VP (VBZ goes) (PP (IN by) (NP (NP (DT the) (NNS veins)) (VP (VBN become) (ADVP (RBR more) (CC and) (RBR more) (RB tortuous)) (, ,) (SBAR (IN while) (S (NP (NP (DT the) (NNS capillaries)) (PP (IN of) (NP (DT the) (NN mucosa)))) (VP (VBP are) (ADVP (RB gradually)) (ADJP (ADJP (JJ dilate)) (CC and) (ADJP (RB precapillary) (JJ sphincter)))))))))))) (VP (VBZ becomes) (NP (JJ incompetent))) (. .)))
As time goes by the veins become more and more tortuous, while the capillaries of the mucosa are gradually dilate and precapillary sphincter becomes incompetent.
(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)))))) (. .)))