West Resp Physio 9th Ed Flashcards
Smallest airways without alveoli
Terminal bronchioles
Average volume of anatomic dead space
150 mL
On average erythrocytes spend how much time in pulmonary capillary network?
0.75 seconds
Volume of respiratory zone of lung
2.5-3 liters
Methods of measuring total lung capacity, FRC or residual volume
Helium dilution technique, helium is insoluble in blood. Body plethysmograph.
Equation for measuring FRC with helium dilution technique
C1V1 = C2(V1+V2), solve for V2
Diffusion described by Fick’s Law
Diffusion ~ D * (P1-P2) * A/T D diffusion constant P1 partial pressure P2 partial pressure A area T thickness
Area of blood gas barrier in lungs
50-100 square meters
Thickness of blood gas barrier in lung
0.3 micrometers
Normal value of diffusing capacity for carbon monoxide at rest
25 mL/min/mmHg, increases 2-3 times with exercise
How much faster is CO2 diffusion through tissue than O2?
20 times because of higher solubility
Diffusion constant is proportional to
Solubility of gas
Diffusion constant is inversely proportional to
Square root of molecular weight of gas
Equation for diffusing capacity of lung for carbon monoxide
DL = VCO / PACO
VCO volume of carbon monoxide
PACO alveolar partial pressure of carbon monoxide
Four causes of hypoxemia
Hypoventilation
Shunt
V/Q mismatch
Diffusion limitation