pulmonary blood flow Flashcards
where do extra-alveolar capillaries arise from?
left ventricle
what is the purpose of extra-alveolar caps
to deliver oxygen and CO2 to the tissue of the lungs
what is venous admixture of extra-alveolar capillaries
blood sent to lung tissue is more oxygen rich than Co2 rich then returns to the left atrium via the pulmonary veins and this mixes blood which causes a little bit more pCO2 than before the blood was sent out.
-does this for convenience and location
Alveolar capillary:
Source
right ventricle
AC:
PaO2
low
AC:
PaCO2
high
AC:
Function
Gas exchange
AC: return to the heart
Pulmonary vein
AC: Blood gases
High PaO2/Low PaCOw
Extra-alveolar Capillary:
source
left ventricle
EAC:
Pa02
high
EAC:
PaCO2
low
EAC:
Fucntion
provide nutrients/remove waste from the tissue of the lungs
EAC:
Return to the heart
pulmonary vein
EAC:
Blood gases
Low Pa02/High PaCO2
Pulmonary vascular resistance
PBP = CO X PVR
usual pulmonary BP
25/15
mean arterial pressure?
diastolic BP + 1/3 pulse pressure
pulmonary vascular resistance must be about ___ of the systemic system
1/4
what determines the pulmonary vascular resistance?
high number of capillaries, how many are open at a given time, much less sympathetic tone/vasocontricing forces
during exercise, PVR (drops or raises)
drops, as more pulmonary capillaries open up to accommodate the increased cardiac output
Pulmonary vascular resistance depends on lung volume
at very high lung volumes or low the resistance increases
Regional blood flow Pa, PA, PV 1) zone I 2) zone II 3) zone III
1) PA>Pa>PV
2) Pa>PA>PV
3) Pa>PV>PA
