MHT CET 202621 AprilEvening Shift
- Exam
- MHT CET
- Year
- 2026
- Date
- 21 April
- Shift
- Evening Shift
- Subject
- Biology
- Chapter
- Breathing and Exchange of Gases
MHT CET 2026 · 21 April · Evening Shift · Biology · Breathing and Exchange of Gases
Which of the following doesn't happen during inspiration?
Which of the following doesn't happen during inspiration?
Options
- AThe intercostal muscle contract
- BThe ribs are pulled outward
- CThe diaphragm lifts upward
- DVolume of thoracic cavity increases
Correct answer
C. The diaphragm lifts upward
Step-by-step solution
During inspiration, the diaphragm contracts and moves downward (flattens), which increases the volume of the thoracic cavity in the antero-posterior axis. It does not lift upward. The lifting upward of the diaphragm occurs during expiration when it relaxes and returns to its original dome shape.
The external intercostal muscles contract, pulling the ribs and sternum upward and outward, which increases the volume of the thoracic cavity in the dorso-ventral axis. This overall increase in thoracic volume leads to a decrease in intrapulmonary pressure, causing air to move into the lungs.
Answer: The diaphragm lifts upward
The external intercostal muscles contract, pulling the ribs and sternum upward and outward, which increases the volume of the thoracic cavity in the dorso-ventral axis. This overall increase in thoracic volume leads to a decrease in intrapulmonary pressure, causing air to move into the lungs.
Answer: The diaphragm lifts upward