PHYSL 210 Lecture Notes - Lecture 2: Transpulmonary Pressure, Alveolar Pressure, Intrapleural Pressure

• School: University of Alberta
• Department: Physiology
• Course: PHYSL 210
• Professor: Dr. Saswati Das

Document Summary

Relative pressures shown in cm of water (in repsratory physiology) Why do you think in the upright lung, the pressure at the bottom is greater at the bottom than the top. At the end of normal expiration, the intrathoracic pressure is -5cm of water (need to know. Alveolar pressure (inside pressure in lungs) compared to outside pressure (atmospheric pressure) Need to regenerate di erence for air ow. Because it suggests that atmospheric pressure is zero. Increase alveolar pressure (to make air ow positive) Question : how can the system decrease alveolar pressure. During inspiration it contracts and goes down. Immediate pressure inside minus the intrapleural pressure. Any trans pressure is the only valid pressure surrogate for volume. Other pressure measurements will sometimes follow volume and sometimes will not. So if trans pulmonary pressure goes up, lung volume must be going up and vice versa. It is easier to take a pressure measurement than an accurate volume measurement.