<prompt> Pulmonary circulation differs from systemic circulationPulmonary vasodilatation in hypoxiaPulmonary vasoconstriction in hypoxiaDecreased blood volume during systoleIncreased basal vasoconstrictor tone  <response>: Hypoxic pulmonary vasoconstriction HPV, also known as the Euler-Liljestrand mechanism, is a physiological phenomenon in which small pulmonary aeries constrict in the presence of alveolar hypoxia low oxygen levels. Ref: guyton and hall textbook of medical physiology 12 edition page number: 354,355,356 