Pulmonary Circulation Flashcards
(12 cards)
How are the bronchi drained?
Right to the azygos vein (small)
Left to the accessory hemiazygos vein (small)
Majority goes back with pulmonary veins to left atrium (right to left shunt)
Why is the pulmonary circuit low pressure?
It only needs to pump blood to the top of the lungs and decreases edema
What does a small increase in pulmonary arterial pressure lead to?
Large increase in compliance
Large decrease in pulmonary vascular resistance
Large increase in pulmonary capillary flow
When is PVR lowest?
At functional residual capacity
What are extra-alveolar vessels?
Vessels outside of the alveoli that are affected by the transmural pressure
What occurs to extra-alveolar vessels with more negative intrapleural pressure?
Decreases resistance
Why do hypoxic areas of the lungs not receive blood flow?
To shunt blood to areas of the lungs that are able to receive oxygen
Why is pulmonary vascular resistance lowest at functional residual capacity?
Recruitment and distension of pulmonary capillaries
What happens to areas of the lungs that are hypoxic and hypoventilated?
The arteries vasoconstrict
What is the strongest signal for alveolar artery constriction?
Hypoxia (hypoxic vasoconstriction)
An increase in what can cause pulmonary edema?
Hydrostatic pressure
What secondary purpose can the lungs serve?
As a reservoir for particles from the LV before reaching the systemic circulation
