PNB 2265 Lecture Notes - Lecture 17: Pulmonary Pleurae, Intrapleural Pressure, Pleural Cavity

• School: UConn
• Department: Physiology and Neurobiology
• Course: PNB 2265
• Professor: Kristen Kimball

Document Summary

Air moves in and out of lungs by bulk flow: f = change in pressure/r. Pressure within alveoli, equalizes between breaths (with patm) Pressure in intrapleural fluid, about 4 mm hg less than palv (up to about. Transpulmonary pressure (ptp) = palv - pip. Pressure difference holding lungs open (opposes inward elastic recoil of the lung) Since patm > pip, chest wall is actually slightly compressed. Chest wall (pcw) = pip - patm. Pressure difference holding chest wall in (opposes outward elastic recoil of the chest wall) Thoracic volume high, pip becomes more negative, ptp increases, lung volume Mechanism of negative pressure in intrapleural space (pip) Two forces try to pull lungs (via visceral pleura) away from thorax wall (parietal pleura) Surface tension of alveolar fluid ( tries to collapse alveoli) Transpulmonary pressure - opposing force that keeps lungs open: Note: surface tension created by pleural fluid glues visceral pleura (and lungs) to parietal pleura.