| Question |
Answer |
| Fick's law in relation to gas exchange |
Gas diffuses at a rate directly proportional to tissue area and the pressure gradient of the gases on both sides of the membrane |
| tidal volume |
air volume moved during either the inspiratory or expiratory phase of breathing cycle |
| inspiratory reserve volume |
reserve ability for inspiration |
| expiratory reserve volume |
the amount of air left when subject exhales, then continues to exhale and force out additional air |
| forced vital capacity |
total volume of air voluntarily moved in one breath |
| residual lung volume |
air volume remaining in lungs after exhaling as deeply as possible |
| total lung capacity (TLC) |
= RLV(residual lung volume) + FVC(forced vital capacity) |
| helium dilution method |
way to indirectly measure RLV; subject exhales normally then rebreathes a known helium mixture for 5 mins |
| oxygen dilution method |
more rapid assessment of RLV than helium dilution; determines RLV from dilution of lung's original nitrogen concentration, achieved by rapidly rebreathing a volume of 5 L of 100% oxygen |
| maximum voluntary ventilation |
evaluates ventilatory capacity with rapid and deep breathing for 15 secs. |
| minute ventilation |
volume of air breathed each minute; MINUTE VENTILATION = BREATHING RATE X TIDAL VOLUME |
| ventilation-perfusion ratio |
a ratio signifying that alveolar ventilation matches each liter of pulmonary blood flow |
| dyspnea |
inordinate shortness of breath or subjective distress in breathing |
| Valsalva maneuver |
forced exhalation against a closed glottis; can cause an acute drop in BP |
Ch.18 LTI-MA 509
