( ( The ( ( parasympathetic nervous ) system ) ) ( ( ( slows down ) ( some ( of ( these systems ) ) ) ) . ) )
(ROOT (S (NP (DT The) (ADJP (JJ parasympathetic) (JJ nervous)) (NN system)) (VP (VBZ slows) (PRT (RP down)) (NP (NP (DT some)) (PP (IN of) (NP (DT these) (NNS systems))))) (. .)))
The parasympathetic nervous system slows down some of these systems.
(ROOT (S (NP (DT The) (JJ parasympathetic) (NN system)) (VP (MD can) (ADVP (RB also)) (VP (VB be) (VP (VBN referred) (S (VP (TO to))) (PP (IN as) (NP (DT the) (JJ craniosacral) (NN system)))))) (. .)))