( ( ( Composed mainly ) ( of ( hormone-producing ( chromaffin cells ) ) ) ) ( , ( ( the ( adrenal medulla ) ) ( ( is ( ( the ( principal site ) ) ( of ( ( the conversion ) ( of ( ( the ( amino ( acid tyrosine ) ) ) ( into ( ( ( ( ( ( the ( catecholamines epinephrine ) ) , ) norepinephrine ) , ) and ) dopamine ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (VBN Composed) (ADVP (RB mainly)) (PP (IN of) (NP (JJ hormone-producing) (NN chromaffin) (NNS cells))))) (, ,) (NP (DT the) (JJ adrenal) (NN medulla)) (VP (VBZ is) (NP (NP (DT the) (JJ principal) (NN site)) (PP (IN of) (NP (NP (DT the) (NN conversion)) (PP (IN of) (NP (NP (DT the) (JJ amino) (JJ acid) (NN tyrosine)) (PP (IN into) (NP (NP (DT the) (JJ catecholamines) (NN epinephrine)) (, ,) (NP (NN norepinephrine)) (, ,) (CC and) (NP (NN dopamine)))))))))) (. .)))
Composed mainly of hormone-producing chromaffin cells, the adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines epinephrine, norepinephrine, and dopamine.
(ROOT (S (NP (NNS Catecholamines)) (VP (VBP are) (NP (NP (DT a) (NN class)) (PP (IN of) (NP (JJ amine) (NNS hormones))) (SBAR (WHNP (WHNP (DT that)) (NP (WRB when) (JJ synthesised))) (S (VP (VBP form) (NP (DT the) (JJ amino) (NN acid) (NN tyrosine))))))) (. .)))