NEETZoologyBreathing and Exchange of Gases
What is a spirometer used for?
Options
- ATo measure the volume of air involved in breathing movements
- BTo measure the strength of inspiration and expiration
- CTo measure the number of breaths taken per minute
- DTo assess overall health
Correct answer
A. To measure the volume of air involved in breathing movements
Step-by-step solution
The contraction of external inter-costal muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis.The overall increase in the thoracic volume causes a similar increase in pulmonary volume. An increase in pulmonary volume decreases the intra-pulmonary pressure tless than the atmospheric pressure which forces the air from outside to move into the lungs, i.e., inspiration. Relaxation of the diaphragm and the inter-costal muscles returns the diaphragm