( ( ( ( Excretory ( system Kidneys ) ) and ) ( bladder ( and ( associated tubes ) ) ) ) ( , ( ( ( are often ) ( considered ( the ( urinary system ) ) ) ) . ) ) )
(ROOT (S (NP (NP (JJ Excretory) (NN system) (NNS Kidneys)) (CC and) (NP (NN bladder) (CC and) (VBN associated) (NNS tubes))) (, ,) (VP (VBP are) (ADVP (RB often)) (VP (VBN considered) (NP (DT the) (JJ urinary) (NN system)))) (. .)))
Excretory system Kidneys and bladder and associated tubes, are often considered the urinary system .
(ROOT (S (NP (JJ Kidney) (NNS stones)) (VP (VBP are) (VP (VBN considered) (NP (NP (DT a) (NN disease)) (SBAR (WHNP (WDT that)) (S (VP (VBZ affects) (NP (DT the) (JJ urinary) (NN system)))))))) (. .)))