CMD 272 Lecture Notes - Lecture 8: Vocal Tract, Hyoid Bone, Exhalation
2 Nov 2016
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Document Summary
Atmospheric pressure (patm) serves as the reference. When vocal folds open; pm = ps. Alveolar (present within the individual alveolus): pal. When vocal folds open; pm = ps = pal. Pleural/intrapleural (in the space between visceral and parietal pleura): ppl. Thorax size increases for respiration pal drops (boyle"s law) by -2 cm h2o (measure of pressure) Pleurae provide a low-friction surface for movement. O2 and co2 diffuse across the alveolus-capillary boundary. Thorax size decreases for expiration pal increases to +2 cm h2o. Diaphragm contraction causes intrapleural pressures to become even more negative than usual. Lungs are always expanding due to their size relationship to the thorax. Ps and pm are directly related to lung status when vocal folds are open one open. Inspiration = pressure at both locations is negative. Expiration = pressure at both locations is positive. Ps immediately increases as lungs continue expansion. = large pressure difference between ps and pm.
