( ( The hypoxia ) ( ( ( ( ( ( dilates ( ( ( precapillary sphincters ) ( as ( well as ) ) ) arterioles ) ) , ) ( so ( that ( ( more capillaries ) ( will ( be open ) ) ) ) ) ) , ) ( ( reducing ( the distance ) ) ( ( ( ( ( the oxygen ) ( has ( to ( cover ( ( getting ( from capillaries ) ) ( to ( the ( respiring cells ) ) ) ) ) ) ) ) , ) so ) ( that ( ( ( the diffusion ) ( of oxygen ) ) ( is increased ) ) ) ) ) ) ; ) )
(ROOT (S (NP (DT The) (NN hypoxia)) (VP (VBZ dilates) (NP (NP (JJ precapillary) (NNS sphincters)) (CONJP (RB as) (RB well) (IN as)) (NP (NNS arterioles))) (, ,) (SBAR (RB so) (IN that) (S (NP (JJR more) (NNS capillaries)) (VP (MD will) (VP (VB be) (ADJP (JJ open)))))) (, ,) (S (VP (VBG reducing) (NP (DT the) (NN distance)) (SBAR (SBAR (S (NP (DT the) (NN oxygen)) (VP (VBZ has) (S (VP (TO to) (VP (VB cover) (S (VP (VBG getting) (PP (IN from) (NP (NNS capillaries))) (PP (TO to) (NP (DT the) (VBG respiring) (NNS cells))))))))))) (, ,) (CC so) (SBAR (IN that) (S (NP (NP (DT the) (NN diffusion)) (PP (IN of) (NP (NN oxygen)))) (VP (VBZ is) (VP (VBN increased))))))))) (: ;)))
The hypoxia dilates precapillary sphincters as well as arterioles, so that more capillaries will be open, reducing the distance the oxygen has to cover getting from capillaries to the  respiring cells, so that the diffusion of oxygen is increased;
(ROOT (S (NP (DT The) (JJ abnormal) (NNS cells)) (VP (VP (MD can) (RB not) (VP (VB carry) (NP (NN oxygen)) (ADVP (RB properly)))) (CC and) (VP (MD can) (VP (VB get) (VP (VBN stuck) (PP (IN in) (NP (NNS capillaries))))))) (. .)))