( ( Hypoxic hypoxia ) ( ( occurs ( ( ( ( when not ) ( ( enough oxygen ) ( is ( in ( the air ) ) ) ) ) or ) ( when ( ( decreasing ( atmospheric pressures ) ) ( ( prevent ( ( the diffusion ) ( of ( O 2 ) ) ) ) ( from ( ( the lungs ) ( to ( the bloodstream ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Hypoxic) (NNP hypoxia)) (VP (VBZ occurs) (SBAR (SBAR (WHADVP (WRB when) (RB not)) (S (NP (JJ enough) (NN oxygen)) (VP (VBZ is) (PP (IN in) (NP (DT the) (NN air)))))) (CC or) (SBAR (WHADVP (WRB when)) (S (NP (VBG decreasing) (JJ atmospheric) (NNS pressures)) (VP (VBP prevent) (NP (NP (DT the) (NN diffusion)) (PP (IN of) (NP (NNP O) (CD 2)))) (PP (IN from) (NP (NP (DT the) (NNS lungs)) (PP (TO to) (NP (DT the) (NN bloodstream)))))))))) (. .)))
Hypoxic hypoxia occurs when not enough oxygen is in the air or when decreasing atmospheric pressures prevent the diffusion of O 2 from the lungs to the bloodstream.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (VP (VBN transferred) (PP (IN into) (NP (DT the) (NN bloodstream))) (PP (IN by) (NP (JJ simple) (NN diffusion))))) (. .)))