PHYSL 210 Lecture Notes - Lecture 3: Ideal Gas Law, Transpulmonary Pressure, Alveolar Pressure
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One complete cycle of inspiration and expiration. Frc at a. frc = end of normal expiration. Alveolar pressure is 0 as air ow is 0. P_tp = {alveolar pressure - pleural pressure (0-(-5)) =5. If lung volume is going up then alveolar pressure must be coming down. P_tp goes up as lung volume goes up. P_tp : good surrogate marker of lung volume. C is a static condition, no air ow, no alveolar pressure. If lung volume is going down, alveolar pressure is going up (to around 2cm h2o) Right after b and right after d , boyle"s law not followed. 150ml of that is caught in anatomical dead space (no gas exchange) Vd does not partake in gas exchange. Does not tell us the ventilation in alveoli that partakes in gas exchange. Va (more useful) : always less than minute ventilation because you always have dead space.