( ( ( ( The ( nervous ( , ( circulatory ( , ( skeletal , ) ) ) ) ) ) and ) ( muscular systems ) ) ( ( are ( ( discussed ( from ( the cellular ) ) ) ( to ( the ( organ ( systems level ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ nervous) (, ,) (JJ circulatory) (, ,) (NN skeletal) (, ,)) (CC and) (NP (JJ muscular) (NNS systems))) (VP (VBP are) (VP (VBN discussed) (PP (IN from) (NP (DT the) (JJ cellular))) (PP (TO to) (NP (DT the) (NN organ) (NNS systems) (NN level))))) (. .)))
The nervous, circulatory, skeletal, and muscular systems are discussed from the cellular to the organ systems level.
(ROOT (S (ADVP (RB Together)) (, ,) (NP (DT the) (JJ muscular) (CC and) (JJ skeletal) (NNS organs)) (VP (VBP are) (VP (VBN known) (PP (IN as) (NP (DT the) (JJ musculoskeletal) (NN system))))) (. .)))
Together, the muscular and skeletal organs are known as the musculoskeletal system.