( ( The ( proximal tubule ) ) ( ( ( regulates ( ( the pH ) ( of ( the filtrate ) ) ) ) ( by ( ( exchanging ( hydrogen ions ) ) ( in ( ( the interstitium ) ( for ( ( bicarbonate ions ) ( in ( the filtrate ) ) ) ) ) ) ) ) ) ; ) )
(ROOT (S (NP (DT The) (JJ proximal) (NN tubule)) (VP (VBZ regulates) (NP (NP (DT the) (NN pH)) (PP (IN of) (NP (DT the) (NN filtrate)))) (PP (IN by) (S (VP (VBG exchanging) (NP (NN hydrogen) (NNS ions)) (PP (IN in) (NP (NP (DT the) (NN interstitium)) (PP (IN for) (NP (NP (JJ bicarbonate) (NNS ions)) (PP (IN in) (NP (DT the) (NN filtrate))))))))))) (: ;)))
The proximal tubule regulates the pH of the filtrate by exchanging hydrogen ions in the interstitium for bicarbonate ions in the filtrate;
(ROOT (S (NP (NP (NNP Processing)) (PP (IN of) (NP (NP (NN filtrate)) (PP (IN in) (NP (DT the) (JJ proximal) (NN tubule)))))) (VP (VBZ helps) (VP (VB maintain) (NP (DT the) (NN ph) (NN level)) (PP (IN in) (NP (NN body) (NN fluid))))) (. .)))