Lung Vasculature

Question 1

What are the two types of circulation?

Answer 1

1) Pulmonary: From RV (100% BF)

2) Bronchial: 2% LV and supplies architecture

Question 2

Describe structure of Pulmonary artery?

Systemic is opposite

Answer 2

1) Thin vessel wall
2) Minor muscularization
3) No need for redistribution

Question 3

What is the pathway of Pulmonary circulation to lungs?

Answer 3

RV to PArtery to PArterioles to Alveoli

Question 4

Pathway of Bronchial artery and clinical relevance?

Answer 4

Bronchial Artery –> Bronchial Tree –> Architecture of Lungs
(If PA blocked, lung doesn’t die as still supplied by BA)

Question 5

How do pulmonary artery structure differ from systemic?

Answer 5

Much thinner layers due to low pressure

Question 6

Importance of radius on resistance?

Answer 6

Small change to diameter of tube has large effect on resistance

Question 7

How to calculate pressure across PC?

Answer 7

Pa across Circuit = CO x R

Question 8

Further equation for Pressure

Answer 8

mPAP-PAWP = CO x PVR

Question 9

Why does mPAP remain stable in exercise but CO increase?

Answer 9

Resistance decreases

Question 10

Describe recruitment and Distention?

Answer 10

R: More pathways open up so more blood pass through
D: Existing pathways larger for more blood to go through

Question 11

Describe V/Q in apex of lung?

Answer 11

High, as less perfusion

Question 12

How do you read V/Q graph from L –> R, and how is mismatch shown?

Answer 12

1) Bottom of Lung to Top of Lung

2) Ventilation graph has shallower decrease than blood flow

Question 13

What is V/Q mismatch?

Answer 13

Perfusion of blood in capillaries, doesn’t match alveolar ventilation

Question 14

What is a cause of high V/Q ratio?

Answer 14

Pulmonary Embolism

Question 15

What is it called when low V/Q ratio and what is a cause?

Answer 15

1) Shunt: Lots of perfusion, no ventilation

2) Pulmonary Oedema