Biology - Breathing and Exchange of Gases Question with Solution | TestHub
Which of the following does NOT occur during inspiration ?
Options:
Answer:
Solution:
During inspiration, the diaphragm contracts and becomes flat, increasing the volume of the thoracic cavity in the antero-posterior axis.
The external intercostal muscles contract, lifting the ribs and sternum upward and outward, which increases the volume of the thoracic cavity in the dorso-ventral axis.
The overall increase in thoracic volume leads to an increase in pulmonary volume.
According to Boyle's law, an increase in volume results in a decrease in pressure. Thus, the intra-pulmonary pressure decreases below atmospheric pressure, causing air to rush into the lungs.
An increase in the pressure of the thorax and lungs occurs during expiration, not inspiration.
Answer: Increase in pressure of thorax and the lungs.
