Question

Expansion of the chest wall means the diaphragm moves _____ and the chest wall moves __________.

a) Upward, outward
b) Downward, outward
c) Upward, inward
d) Downward, inward

Answer 1

During the expansion of the chest wall, the diaphragm moves downward and the chest wall moves outward. This allows air to enter the lungs during inhalation.

Step-by-step explanation:

The expansion of the chest wall occurs when the diaphragm moves downward and the chest wall moves outward.

During inhalation, the contraction of the external intercostal muscles causes the chest wall to expand outward to create more space in the thoracic cavity. At the same time, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity.

These movements allow air to enter the lungs, and during exhalation, the diaphragm relaxes and moves upward, while the chest wall returns to its original position.