Respiratory Physiology - Perfusion and Ventilation Flashcards
Where is blood flow the highest in the lungs?
the base
Where is ventilation the highest in the lungs?
the apex
What is the normal V/Q ratio?
0.8
What is the V/Q ratio at the apex?
3.33
ventilation exceeds perfusion
What is the V/Q ratio in the base ofthe lungs?
0.8
perfusion exceeds ventilation
What happens to the areas of the base of the lung with low ventilation but high perfusion? (low partial pressure oxygen)
PCO2 increases and PO2 decrease
the bronchodilation occurs and vasoconstriction of pulmonary vessels occurs to balance out
How would you describe low PO2 blood of the lungs?
hypoxia
How would you describe the movement of deoxygenated blood from the right to left side of the heart with no O2 increase?
shunt
How would you describe ventilation exceeding perfusion?
(opposite of shunt)
alveolar dead space
more air in alveoli that can participate in gas exchange
Where does alveolar dead space occur in a greater amount? (not just the normal at the apex)
pathological situation - pulmonary embolism
BLOOD CLOTT AND IMPEED BLOOD FLOW
How does the body compensate for a large ventilation but very low perfusion?
pulmonary vessel vasodilation and broncho constriction
What are the partial pressures of O2 and CO2 when ventilation exceeds perfusion drastically?
PCO2 high
PO2 low
