( It ( then ( ( ( passes ( from ( the ( right atrium ) ) ) ) ( into ( ( ( the ( right ventricle ) ) , ) ( which ( ( ( ( pumps ( the blood ) ) ( through ( the ( pulmonary arteries ) ) ) ) ( to ( the lungs ) ) ) ( where ( ( the blood ) ( ( picks up ) ( ( a ( fresh supply ) ) ( of oxygen ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (PRP It)) (ADVP (RB then)) (VP (VBZ passes) (PP (IN from) (NP (DT the) (JJ right) (NN atrium))) (PP (IN into) (NP (NP (DT the) (JJ right) (NN ventricle)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD pumps) (NP (DT the) (NN blood)) (PP (IN through) (NP (DT the) (JJ pulmonary) (NNS arteries))) (PP (TO to) (NP (DT the) (NNS lungs))) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NN blood)) (VP (VBZ picks) (PRT (RP up)) (NP (NP (DT a) (JJ fresh) (NN supply)) (PP (IN of) (NP (NN oxygen))))))))))))) (. .)))
It then passes from the right atrium into the right ventricle, which pumps the blood through the pulmonary arteries to the lungs where the blood picks up a fresh supply of oxygen.
(ROOT (S (NP (NP (DT The) (JJ right) (NN atrium)) (PP (IN of) (NP (DT the) (JJ human) (NN heart)))) (VP (VBD pumps) (NP (DT the) (NN blood)) (PP (TO to) (NP (DT the) (JJ right) (NN ventricle)))) (. .)))