Pulmonary vascular resistance

PULMONARY VASCULAR RESISTANCE

  • Although pulmonary vascular resistance is very low at rest, it can decrease further, as in exercise, during which blood flow increases. Neural : Sympathetic nerves to larger vessels - NE released.
  • Effects somewhat controversial - most likely increases pulmonary vascular resistance and decreases distensibility of larger vessels. Parasympathetic - Ach decreases PVR if tone elevated.
  • Humoral : Increase PVR: Norepinephrine, alpha adrenergic agonists, serotonin, prostaglandins F2 and E2, angiotensin, endothelin, alveolar hypoxia (hypoxic pulmonary vasoconstriction), alveolar hypercapnia, low pH of mixed venous blood.
  • Histamine constricts pulmonary veins. Decrease PVR: Acetylcholine, beta adrenergic agonists, bradykinin, prostaglandin E1 and I2 (prostacyclin), nitric oxide.
Last modified: Saturday, 4 June 2011, 8:52 AM