Pulmonary circulation Flashcards
PVR
pulmonary vascular resistance
pulmonary vascular resistance (PVR) - equation
(Ppulm arter - P left atrium) / cardiac output
resistance - equation
(8 x viscosity x vessel length) / (πr4)
pulmonary circulation - resistance - low or high
low
pulmonary circulation - compliance - low or high
high
pulmonary circulation vs systemic circulation according PO2
in pulmonary circulation, a decreasing in PAO2 causes a HYPOXIC VASOCONSTRICTION
decreased PAO2 associated vasoconstriction in pulmoary circulation - purpose
it shifts blood away from poorly ventilated regions of lung to well-ventilated regions of lung
A consequence of pulmonary hypertension is
cor pulmonale and subsequent right ventricular failure (jugular venous distention, edema, hepatomegaly)
pulmonary circulation - perfusion limited (definition)
Gas equilibrates early along the length of the capillary
pulmonary circulation - perfusion limited –> perfusion can be increased ….
only by blood flow increasing
pulmonary circulation - perfusion limited - example gases
- O2 (NORMAL HEALTH)
- CO2
- N20
pulmonary circulation - diffusion limited (definition)
gas does not equilibrate by the time blood reaches the end of the capillary
pulmonary circulation - diffusion limited - example gases
- O2 (under emphysema, fibrosis)
2. CO
pulmonary circulation - diffusion vs perfusion limited in exercise
normally gas EQUILIBRATES but at the end of the capillary
diffusion equation
Vgas = (A/T) x DK (P1-P2)
DK (P1-P2) is the difference in partial pressures
A:area
T:alveolar wall thickness
