Coronary flow

  • high metab demand
  • high oxgen extraction
  • metabolic hyperaemia mediated by adenosine, K+, hypoxia

effect of sympathetic stimulation

  • alpha adrenergic effect = vasoconstriction
  • however hyperaemia probably overrides this
  • adrenaline → vasodilation (beta adrenergic action)

effect of parasympathetic stimulation

  • parasympathetic stimulation → vasodilation