Pulmonary Circulation

Question 1

Why is bronchial circulation different?

Answer 1

It is a shunt due to the bronchial capillary venous blood going into the pulmonary veins.

Question 2

What are the average pressures in systemic vs pulmonary?

Answer 2

Systemic 100

Pulmonary 10

Systemic is 10x greater

Question 3

Where is the pressure in pulmonary artery greatest? Least?

Answer 3

Greatest at the bottom

Least at the top

Question 4

In zone 1, what occurs in terms of perfusion?

Answer 4

PA>Pa>Pv

The pathway is pinched and profusion does not occur.

Question 5

When does zone 2 perfuse?

Answer 5

During Systolic

No perfusion during diastolic

Pa>PA>Pv

Question 6

Is zone 3 of the lung perfused? Where is it?

Answer 6

Pa>Pv>PA

It is perfused.

It is at the bottom of the lung.

Question 7

What mechanism occurs in the lung whenever a portion is poorly ventilated

Answer 7

The local vascular resistance is increased and sends blood elsewhere.

Smoking/COPD makes this not work.

Question 8

If PO2 in the lung is low, what occurs?

Answer 8

Pulmonary vasoconstriction.

This caused the right heart to work much harder and can lead to right heart failure.

Question 9

Why does PVR not change much during exercise?

Answer 9

Recruitment (opening of collapsed arteries)

Distension (Increasing radius of existing vessels)

Question 10

How do lungs resistance add?

If you removed a lung, what would happen to PVR?

Answer 10

1/R=1/left+1/right

Removing a lung causes PVR to rise