Common lung pathologies affecting diffusions

Question 1

emphysema

Answer 1

destruction of alveoli reduces surface area for gas exchange

Question 2

fibrotic lung disease

Answer 2

thickened alveolar membrane slows gas exchange. loss of lung compliance may decrease alveolar ventilation

Question 3

asthma

Answer 3

increased airway resistance decreases airway ventilation (bronchioles constrict)

Question 4

pulmonary oedema

Answer 4

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