BIO 115 Lecture Notes - Lecture 9: Fluid Balance, Intermolecular Force, Intrapleural Pressure
Document Summary
The rubber band can be seen as analogous to the lung if pressure is substituted for force and volume is substituted for distance. Plotting pressure vs volume yields a relatively linear curve. Reducing the pressure gradient across the chest wall (e. g. increasing pip toward 0) increases thoracic volume. 0. 2 l/cm h2o: compliance of the lung + chest wall: The forces of capillary action bind the lung and chest wall together. These two compliant systems are in series, so the total compliance must be less than either component individually. The system is more difficult to stretch. (imagine inflating a balloon inside another balloon) 1/c(resp) = 1/c(lung) + 1/c(chest: near frc, where: c(lung) = c(chest) = 0. 2 l/cm h2o, c(resp) = 0. 1. Small bubbles have a greater internal pressure than larger bubbles. Surface forces tend to pull interstitial fluid into the alveolus. The constant (2) varies as a function of the geometry of the object in question.
