03.1 Gas Exchange Flashcards
Which diffuses faster, O2 or CO2 and what factors contribute to this?
O2 is smaller which increases its diffusion speed.
CO2 is more soluble which increases its diffusion speed.
Overall CO2 is quicker.
How does fibrotic lung disease impair diffusion?
Thickened alveolar membrane slows gas exchange.
What impairs diffusion in pulmonary oedema?
An increase in diffusion distance.
What impairs diffusion in emphysema?
Reduces surface area
What is the ideal VQ ratio?
1
What can decrease the VQ towards 0?
Blocking the airways
What can cause the VQ ratio to increase towards infinity?
Blockage of the pulmonary arteries.
What is anatomical dead space?
The volume of air in the conducting portion of the lungs
What is distributive/alveolar dead space?
Poorly perfused/damaged alveoli
What is total dead space also known as?
Physiological dead space
What is the pulmonary ventilation rate?
Tidal volume X respiratory rate
What is alveolar ventilation rate?
Pulmonary ventilation rate - (total dead space X resp rate)
According to Fick’s law what has an affect on gas exchange?
Pressure difference Solubility of gas in solution Cross sectional area of fluid Distance molecules must diffuse Molecular weight of the gas Temperature isn't considered as it is at a constant 37 degrees C.
