Question 12
RespirationWhich of the following actions does not occur during exhalation in man?
- A.Thoracic cavity decreases in volume
- B.Diaphragm flattens
- C.Ribs move down and in
- D.Air pressure increases in the thoracic cavity
Show the answer and explanation
Answer: B (Diaphragm flattens)
Explanation
When we breathe out, the diaphragm relaxes and curves upwards, the ribs move down and in, the chest volume falls and the pressure inside rises, pushing air out. The diaphragm flattens only when we breathe in.