( ( The ( menstrual cycle ) ) ( ( is ( controlled ( by ( mechanisms ( involving ( hormones ( released ( by ( ( ( ( ( ( the hypothalamus ) , ) ( the pituitary ) ) , ) and ) ( the ovaries ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ menstrual) (NN cycle)) (VP (VBZ is) (VP (VBN controlled) (PP (IN by) (NP (NP (NNS mechanisms)) (PP (VBG involving) (NP (NP (NNS hormones)) (VP (VBN released) (PP (IN by) (NP (NP (DT the) (NNS hypothalamus)) (, ,) (NP (DT the) (NN pituitary)) (, ,) (CC and) (NP (DT the) (NNS ovaries))))))))))) (. .)))
The menstrual cycle is controlled by mechanisms involving hormones released by the hypothalamus, the pituitary, and the ovaries.
(ROOT (S (NP (NP (DT The) (NN release)) (PP (IN of) (NP (NP (DT an) (NN egg)) (PP (IN from) (NP (DT an) (NN ovary)))))) (, ,) (VP (VBZ is) (NP (NP (NN part)) (PP (IN of) (NP (DT the) (JJ menstrual) (NN cycle))))) (. .)))