Common Lung Pathologies

Question 1

What is the effect of emphysema?

Answer 1

Reduced alveolar surface area.
Easier inspiration but difficult expiration.

Question 2

What is the effect of fibrotic lung disease?

Answer 2

Thickened alveolar membrane.

Question 3

How can fibrotic lung disease decrease alveolar ventilation?

Answer 3

A loss of lung compliance.
Inhaling becomes difficult, so less O2 gets into the alveoli, and the partial pressure gradient decreases. PO2 decreases in circulation.

Question 4

What is the effect of pulmonary oedema?

Answer 4

Fluid in the interstitial space increases diffusion distance.
Arterial PCO2 may be normal due to higher CO2 solubility in water.

Question 5

What is the effect of asthma?

Answer 5

Increased airway resistance decreases airway ventilation and does not directly affect diffusion.