Respiratory Physiology - Pulmonary Blood Flow Flashcards
The pressure on the R heart is greater or less than the L heart
Greater
Both sides of the heart pump how much blood
The same
50 ml
What is the systolic pressure of the LV and RV
LV = 120 mmHg RV = 25 mmHg
What is the diastolic pressure in the ventricles and what does this mean
0 mmHg
Blood does not flow back in passively
What is the pressure for the LA and RA and what does this mean
15/4 - slight diastolic pressure which means blood comes in passively
What is the typical CO at rest
5 Lpm
When the heart begins to fail, where does the blood back up
The lungs
What is the pressure of the Ao and PA
Ao - 120/80
PA - 25/15
Extra-alveolar capillaries receive blood from where
The LV
What is the role of the extra-alveolar capillaries
Deliver O2 to the tissue of the lungs
What doe the extra-alveolar capillaries feed back into
The pulmonary veins
What is the PaO2 in the artery of the alv. And extra-alv. Capillaries respectively
Alv. - low
Extra-alv. - high
What is the O2 in the venous return to the PV in the alv. And extra-alv. Capillaries respectively
Alv. - high O2
Extra alv. - low O2
What is the equation for Pulmonary BP
PBP = CO x PVR
Pulmonary vascular resistance is higher or lower than in the periphery? And what does this mean
Lower, this means we can move more blood across the lungs to get them oxygenated and supply the body
What is the main thing that determines PVR
How many alveoli are open at any given moment in time
What happens during exercise in the PVR and why does this happen and what does it allow?
PVR drops because more alveoli are open
This allows the lungs to accommodate the increased CO and allow for more oxygenation of RBCs
The blood pressure in the lungs is higher or lower in the apex (zone I) of the heart? What about the blood flow and the alveoli?
The blood pressure is lower, yet the alveoli are more expanded
Blood flow is less
The blood pressure in the lungs is higher or lower in zone II of the heart? What about the blood flow and the alveoli?
The blood pressure is about the same as the heart with a normal blood flow
The alveoli are average in size
The blood pressure in the lungs is higher or lower in the base (zone III) of the heart? What about the blood flow and the alveoli?
The blood pressure is highest due to being below the heart
The alveoli are smaller
The blood flow is greatest here
What does NO do and what produces it?
Made by the vascular endothelium
Causes smooth muscle relaxation and vasodilation during normal pulmonary blood flow
If the alveolie are “dry” what can better happen
O2 can move easier across capillaries into the alveoli
What is the capillary hydrostatic pressure
Blood pressure in the capillary, contributes most to starling forces
Is trying to push fluid into the alveoli
What is the tissue hydrostatic pressure and what role does it play in the starling forces
Pressure in the tissue which SHOULD push fluid into the capillary, HOWEVER since the intrapleural cavity is NEGATIVE, the Pt actually helps push fluid into the alveoli
What is the plasma oncotic pressure
This is the capillary oncotic pressure
It tries to pull water into the capillary
What is the tissue oncotic pressure
Tries to pull water into the alveolus
So in the lung, what is the only force moving water from alveoli to capillary
Tissue oncotic pressure
Equation for starling forces
(Pc + Pi[tissue] + Ptissue) - pi[capillary]
Starling Forces favor the movement of water into the alveoli. This is bad, so how do we fix it?
The lymphatics! Drain excess filtrate from lungs away to the vessels
