Physiology: lung function testing

Question 1

Spirometry: label the terms

Answer 1

Question 2

What are obstructive lung diseases caused by? 2 examples?
What are restrictive lung diseases caused by? 2 examples?

Answer 2

Increased lung resistance - asthma, COPD
Decreased lung elasticity - fibrosis, scoliosis

Question 3

What are the FEV1/FVC ratios in:
- Healthy adults
- Obstructive lung disease
- Restrictive lung disease

Answer 3

80%
<70%
>90%

Question 4

Do you know what volume-time graphs look like for normal, obstructive and restrictive diseases?

Answer 4

Yes

Question 5

Do you understand flow volume loops? What direction do they go in?

Answer 5

Clockwise

Question 6

Do you know what obstructive and restrictive patterns look like?

Answer 6

Yes

Question 7

Can residual volume be measured directly with spirometry?

Answer 7

No

Question 8

How to indirectly measure residual volume with helium?

Answer 8

Question 9

Why is CO used to measure diffusion capacity (how easily substances diffuse over the alveolar membrane?)

Answer 9

Because CO is used up (by hemoglobin) faster than it can diffuse across the membrane - so the only factor limiting CO diffusion is the membrane itself