(10) Respiratory Physiology 2: Pulmonary Blood Flow (Karius) Flashcards
Describe the pressures you’d observe within the:
R/L Atria
R/L Ventricles
What is a typical cardiac output?
(L/min)?
5 L/min
What is the pressure observed in the aorta?
120/80
What is the pressure observed in the pulmonary a.?
25/15
What is hypoxic constriction?
When O2 levels decrease, leads to vasoconstriction
This increases the peripheral vascular resistance
Where do alveolar capillaries receive blood from?
Right ventricle
Blood is low O2, High CO2
What is this image revealing??
Alveolar capillaries
Extra-alveolar capillaries receive blood from?
LEFT ventricle
High O2/Low CO2
Function of extra-alveolar capillaries?
Deliver O2 and CO2 to the tissue of the lungs
LO:
Compare and contrast the alveolar and extra alveolar vessels
What are the differences in sources of blood?
Alveolar Capillary:
Source: RIGHT ventricle via pulmonary artery
Extra-alveolar Capillary:
Source: LEFT ventricle via AORTA
LO:
Compare and contrast the alveolar and extra alveolar vessels
Function of both?
Alveolar Capillary:
Gas exchange in alveoli
Extra-alveolar Capillary:
Provide nutrients to and remove waste from the airways
How do you calculate blood pressure?
How do you calculate the pressure for the lung?
The pulmonary vascular resistance is much __________ than we see in the rest of the body
LOWER
What is pulmonary vascular resistance determined by?
- High number of capillaries
- How many are open at a given time
- Lung volume
Under what circumstances would pulmonary vascular resistance (PVR) DROP?
During EXERCISE!!!
PVR Drops as more pulmonary capillaries open up to accomodate the increased cardiac output
LO:
Compare and contrast the pulmonary vascular resistance with the systemic total peripheral resistance
PVR:
Normal value=LOW
Blood pressure=LOW
Blood volume = 5 L/min
Systemic resistance:
Normal value= Moderate
Blood pressure= Higher
Blood volume = 5 L/min
Draw out the 3 regions of the lung and describe the relative pressures
Zone 1: BP is reduced b/e above level of the heart
Zone 3: Has the highest BP
What are the 4 major chemical modulators of pulmonary blood flow we discussed in lecture?
- Nitric Oxide
- Endothelin 1
- Thromboxane A2
- Oxygen
What are the effects of nitric oxide (NO)?
Causes smooth muscle relaxation and vasodilation
What are the effects of endothelin 1?
Vasoconstrictor
*role in pathologic conditions, not under normal
What are the effects of thromboxane A2?
Similar to endothelin 1
Vasoconstrictor that can be found in right/wrong conditions
What is the effect of oxygen on pulmonary blood flow?
Blood vessels relax in it’s presence
(Low O2 leads to vasoconstriction –> hypoxic vasocontriction –> increased peripheral vascular resistance)
Keeping the alveoli “dry”
What determines whether the water moves from the capillaries to the alveoli?
THE STARLING FORCES
Control how much fluid moves from the capillary to the lung
