Which of the following is measured by the device, Bellow's spirometer?
The spirometer is a simple device for measuring gas volumes. The frequently used water spirometer, rolling seal spirometer and bellows spirometer. The last two are not water-filled and are more poable. The VT, IRV, ERV, IC, and VC can all be measured with a spirometer (as can the forced expiratory volume in 1 second , forced vital capacity , and forced expiratory flow ). The RV, the FRC, and the TLC, however, cannot be determined with a spirometer because the subject cannot exhale all the gas in the lungs. The lung volumes not measurable with spirometry can be determined by the nitrogen-washout technique, by the helium-dilution technique, and by body plethysmography. The FRC is usually determined, and RV (which is equal to FRC minus ERV) and the TLC (which is equal to VC plus RV) are then calculated from volumes obtained by spirometry. Ref: Levitzky M.G. (2007). Chapter 3. Alveolar Ventilation. In M.G. Levitzky (Ed), Pulmonary Physiology, 7e.
TLC
RV
Closing volume
ERV