Question

Which of the following does not take place during expiration?

• A. Diaphragm becomes dome-shaped.
• B. Lungs undergo compression to release the air out.
• C. Volume of the thoracic cavity increases.
• D. Ribs are pulled inwards.

Hint:

During expiration, the diaphragm moves upwards, and the volume of the thoracic cavity decreases.

Answer 1

The Correct Option is C

Step 1: Understanding expiration.
During expiration, the diaphragm relaxes and becomes dome-shaped, and the volume of the thoracic cavity decreases. The lungs are compressed, pushing air out. The ribs are pulled inwards as well.
Step 2: Analyzing the options.
(A) Diaphragm becomes dome-shaped: Correct — This happens during expiration, as the diaphragm moves upwards.
(B) Lungs undergo compression to release the air out: Correct — The lungs compress to expel air.
(C) Volume of the thoracic cavity increases: Incorrect — During expiration, the volume of the thoracic cavity decreases.
(D) Ribs are pulled inwards: Correct — The ribs are pulled inwards during expiration to help compress the lungs.
Step 3: Conclusion.
The correct answer is (C) Volume of the thoracic cavity increases, as this is not part of the expiration process.