| Autor: |
Hixon, Thomas J., Siebens, Arthur A., Ewanowski, Stanley J. |
| Zdroj: |
Journal of the Acoustical Society of America; 1968, Vol. 44 Issue 1, p354-355, 2p |
| Abstrakt: |
The static pressure-volume characteristics of the lungs and thorax (diaphragm included) were measured throughout the vital capacity in five healthy adult males during breath holding with the airways open and during voluntary relaxation against an infinite resistance, respectively. Pressure-volume events were then recorded throughout most of the vital capacity during sustained [[open_aye]] productions at three different vocal-effort levels. Data were plotted in Campbell diagrams and analyzed to determine the alveolar pressures and the net forces developed by the respiratory muscles during the productions. Results indicated that a relatively steady alveolar pressure was provided by the respiratory system, the level of this pressure increasing with successive increases in vocal effort. Maintenance of a steady pressure throughout the lung volume required a continuously changing muscular effort in the face of changing elastic forces. At high lung volumes, the direction of airflow and the net muscular effort were often found to be opposite in sign. This suggests a braking action on the part of the inspiratory muscles. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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