( ( When ( ( an ( olfactory receptor ) ) ( captures ( an ( odor molecule ) ) ) ) ) ( , ( it ( ( triggers ( ( electrical signals ) ( carried ( by ( nerves ( that ( ( run ( from ( the nose ) ) ) ( to ( ( the ( olfactory bulbs ) ) ( inside ( the brain ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT an) (JJ olfactory) (NN receptor)) (VP (VBZ captures) (NP (DT an) (NN odor) (NN molecule))))) (, ,) (NP (PRP it)) (VP (VBZ triggers) (NP (NP (JJ electrical) (NNS signals)) (VP (VBN carried) (PP (IN by) (NP (NP (NNS nerves)) (SBAR (WHNP (WDT that)) (S (VP (VBN run) (PP (IN from) (NP (DT the) (NN nose))) (PP (TO to) (NP (NP (DT the) (JJ olfactory) (NNS bulbs)) (PP (IN inside) (NP (DT the) (NN brain))))))))))))) (. .)))
When an olfactory receptor captures an odor molecule, it triggers electrical signals carried by nerves that run from the nose to the olfactory bulbs inside the brain.
(ROOT (S (NP (NP (DT An) (JJ electrical) (NN signal)) (PP (IN along) (NP (DT a) (NN nerve) (NN cell)))) (VP (VBZ triggers) (NP (NP (DT the) (NN secretion)) (PP (IN of) (NP (NN neurotransmitter) (NNS molecules))))) (. .)))