Pulmonary gas exchange Flashcards
atmospheric pressure at sea level is __
760 mmHg
addition of water causes the partial pressure of other gases to __
decrease
Increasing alveolar ventilation will increase __
PAO2
The rate of gas diffusion across the respiratory membrane depends on
- Difference in Partial Pressures Across the Membrane (ΔP )
- Solubility of Gas in Fluid (S)
- Cross-Sectional Area of Membrane (A)
- Distance of Diffusion (d)
- Molecular Weight of Gas (MW)
V=
ΔP x A x S/ d x √MW
gas exchange at the respiratory membrane depends on
- transport rate
- rate of alveolar ventilation
A tissue with high metabolic activity will have a lower __, creating a __ partial pressure
gradient
PO2, larger
CO2 is more soluble (S) than O2 so CO2 diffuses __
more rapidly
If more pulmonary capillaries are recruited, as in exercise, the surface area (A) available for diffusion __
increases
If the thickness of the diffusion barrier increases (d), such as with Pulmonary Fibrosis or Edema, this __
decreases diffusion
Components of Respiratory Membrane
- Surfactant
- Alveolar Epithelium
- Alveolar Basement Membrane
- Interstitial Space
- Endothelial Basement Membrane
- Capillary Endothelium
Average width of respiratory membrane is __
0.6 μm
Under normal conditions, O2 transport into pulmonary
capillaries is __ limited
perfusion
O2 transport with other conditions (fibrosis, etc) is __ limited
diffusion
diffusing capacity of the lung measures the respiratory membrane’s functional __
integrity