Low lung volumes, atelectasis & ventilation

Question 1

1. Decribe functional residual capacity (FRC)

Answer 1

volume of gas in lungs after normal expiration

Question 2

2. Describe closing capacity

Answer 2

Volume of air in lungs when small airways in dependent lung start to collapse during expiration
-normal CC=RV & CC/= FRC during expiration there may be a collapse of airways in dependent lung areas, resulting in reduced ventilation to those areas

Question 3

3. Describe Hypoxaemic pulmonary vasoconstriction

Answer 3

• V/Q mismatch- decrease Pa02
• Constriction divert blood to areas with greater ventilation –> increase perfusion to areas of increased ventilation –> increase Pa02