PHYSL210B Lecture Notes - Lecture 3: Alveolar Pressure, Tidal Volume, Lung Volumes
13 Jan 2019
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Document Summary
Lung volumes can be measured using spirometry. Tidal volume (vt): normal volume of air inspired and expired by the lungs. Respiratory reserve volume (irv): max volume that can be inspired after a normal inspiration. Expiratory reserve volume (erv): max volume that can be expired after a normal expiration. Residual volume (rv): lungs can never be empty of air. Volume of air that remains in the lungs. As inter thoracic volume decreases, pressure increases and the bronchioles collapse, which traps air inside the alveoli. Two evolutionary benefits of rv: prevent lung collapse if lung collapses, it will be energy expensive to pop them open again, o2 is always available to diffuse in the blood. Vital capacity (vc): vt+ irv+ erv (diagnostic test) Functional residual capacity (frc): erv +rv (air left in the lung after normal expiration. Total lung capacity (tlc)= vt+ erv+ irv+ rv (total lung volume around 6 litres) Atmospheric pressure= 0 trans pulmonary pressure= 0-(-5) =+5.
