KINE 3012 Lecture Notes - Lecture 3: Transpulmonary Pressure, Intrapleural Pressure, Alveolar Pressure
Document Summary
Pressure will drop, so more air will move in. We contract the diaphragm, it flattens, it increases the volume of the intrapleural space, then pressure goes down. When we breathe in, intrapleural pressure from 756 --> 754, thus increasing volume of alveoli and deceasing alveolar pressure causing air to go in. Misconception, we don"t suck air in, air is pushed in due to the changes in pressure, delta p. Air stops going in after alveolar pressure and atmospheric pressure are equal. Thus, when we breathe, we increase transpulmonary pressure. At the end of inspiration, the recoil == transpulmonary pressure, when they stop moving, they are always equal. Diaphragm relax, thorax becomes smaller, volume smaller, intrapleural pressure increases. Transpulmonary pressure decreases, volume of alveoli decreases, alveolar pressure increases higher than atmospheric pressure, air is pushed out of the lungs. When transpulmonary pressure > recoil strength, lungs expand causing the recoil to increase until transpulmonary pressure == recoil strength.