Pulmonary Blood Flow, Ventilation and Perfusion -Karius Flashcards
normal CO
3.5 L/min - 5.0 L/min
Hypoxia response of the pulmonary circulation
vasoconstriction
Hypoxia response of the systemic circulation
vasodilation
PvO2
PvCO2
PvO2 : 40mmHg
PvCO2: 45mmHg
PaO2
PaCO2
PaO2 : 100mmHg
PaCO2 : 40mmHg
what causes vasoconstriction in pulmonary circulation during hypoxia
SM of pulmonary tissues do it themselves to direct blood to areas of good gas exchange
steps in vasoconstriction of the pulmonary vessels
- low O2
- K + leak channels open
- depolarization
- opens Ca+2 LCAT channels
- more depolarization to SM contractions
- vasoconstriction
where do alveoli get blood from and then they go where
the RV —-> LA
where do bronchial (extra-alveolar) capillaries get their blood from
and then they go where
LV * to supply the lung tissues that are far from the alveolar capillaries
—-> 1. Azygous V (–> RA), 2. LV = venous admixture
how to calculate pulmonary BP
CO x PVR(pulmonary vascular Resistance)
= 25/15mmHg (lower then systemic TPR)
BP and capillaries that are open relationship
the more capillaries that are open the lower the PVR
PVR during exercise
decreases due to more capillaries that are open
PVR relationship with lung volume
at very high lung volumes (a lot of air) + at very long lung volumes (Chest wall pushes in)
= Resistance increases because the capillaries get compressed when tissues are stretched or pushed in
main cause of pulmonary HTN
vasoconstriction
(in COPD/emphysema) you also see low SA and capillaries and alveoli die = also increases gas volume inside = increases resistance
what brings blood back up to the heart when knees are not locked
skeletal muscle pump pumping blood back up to the heart and prevents decrease in venous return
3 zones of the lung ZONE 1 alveoli size BF BP and Ps
Zone 1 : apex (biggest avloli, least amount of BF, smallest BP
PA > Pa > Pv
*Pa is close to 140mmHg
3 zones of the lung ZONE 2 alveoli size BF BP and Ps
Zone 2 : middle
medium sized alveoli, normal BF, normal BP equal to BP at level of the heart
Pa> PA > Pv
*Pa is close to 100mmHg
3 zones of the lung ZONE 3 alveoli size BF BP and Ps
Zone 3: base smallest alveoli highest BF highest BP Pa > Pv > PA *Pa is close to 40mmHg
NO function
Para—-> vasodilate
SM relaxation
PULMONARY FLOW, decreases PVR
Endothelin 1 funciton
made in lung
vasoconstrictor , usually under not normal conditions or disease