Impaired gas exchange in lungs Flashcards
What disease state can decrease the surface area of the respiratory membrane?
Emphysema
How does emphysema decrease the surface area of the respiratory membrane?
Alveoli combine, giving larger alveoli but reduced surface area of their walls
How do increased thickness of respiratory membrane, decreased surface area of respiratory membrane affect the rate of diffusion?
Slower rate of diffusion across the respiratory membrane
How do increased thickness of respiratory membrane, decreased surface area of respiratory membrane affect gas exchange?
Reduced gas exchange across respiratory membrane
How do increased thickness of respiratory membrane, decreased surface area of respiratory membrane affect pO2 and pCO2 of the arterial blood in the pulmonary capillaries? Why?
pO2 is low
pCO2 is normal
Because CO2 has a higher diffusion coefficient than O2
therefore diffuses faster, more exchange of CO2
What is the ventilation:perfusion ratio when the ventilation is 0 but the perfusion is normal?
0
What is the ventilation:perfusion ratio when the ventilation is normal but the perfusion is 0?
Infinity
What is the pO2 and pCO2 of the alveoli when the ventilation:perfusion ratio is 0? Why?
No ventilation, but oxygen and carbon dioxide still diffuse between the alveoli and the blood
same pO2 and pCO2 in alveoli as in venous blood flowing through the pulmonary capillaries
What is the pO2 and pCO2 of the alveoli when the ventilation:perfusion ratio is infinity? Why?
No blood flow, no diffusion of oxygen and carbon dioxide between alveoli and blood
same pO2 and pCO2 in alveoli as in upper respiratory tract
What is the relative perfusion of different portions of the lung?
Upper portion of lung is less perfused than lower portion of the lung
What is the relative ventilation:perfusion ratio in the upper part of the lung?
More than 1
How does a larger ventilation:perfusion ratio affect the physiological dead space?
Increased alveolar dead space
increased physiological dead space
