diffusion/ventilation DSA Flashcards
what is FRC
functional residual capacity
volume of gas in the lung after normal expiration
what is residual volume
air remaining in the lungs after maximal expiration
what is inspiratory reserve volume
volume of air that can be inhaled after a normal respiration
what is inspiratory capacity
maximal volume of air that can be inhaled from FRC
what is expiratory reserve volume
volume that can be exhaled after a normal respiration
what is vital capacity
maximal volume that can be expired after maximal inspiration (so includes a forceful expiration)
what is tidal volume
amount of air entering the lungs during normal breathing
what does helium dilution method measure?
FRC
b/c helium is basically insoluble in blood
what does Body Plethysmography measure?
FRC
what is perfusion limitation of gas diffusion?
amount of gas transported is limited by blood flow (partial pressure gradient is not maintained)
what is diffusion limitation of gas diffusion?
amount of gas that is transported depends on the diffusion process (diffusion will continue as long as the partial pressure gradient is maintained)
what are 4 pathological conditions that alter diffusing capacity
• Diffuse interstitial pulmonary fibrosis
– Thickening of the interstitium, alveolar wall and destruction of capillaries
• Chronic obstructive pulmonary disease
– Loss of lung elastic tissue and pulmonary capillaries (decreases surface area and total Hb content)
• Loss of functional lung tissue
– Decreases surface area and Hb content
• Anemia
– Fall in Hb content
