HMS, BM EQ-Bank 862 MC

During inspiration, which of the following occurs?

Diaphragm relaxes and moves upward
Intercostal muscles relax, allowing ribs to move inward
Thoracic cavity volume decreases
Diaphragm contracts and flattens

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\(D\)

Show Worked Solution

D is correct. During inspiration, the diaphragm contracts and flattens, increasing the volume of the thoracic cavity.

Other Options:

A is incorrect: The diaphragm relaxes and moves upward during expiration, not inspiration.
B is incorrect: During inspiration, the external intercostal muscles contract to lift the ribs upward and outward.
C is incorrect: As thoracic cavity volume increases during inspiration, not decreases.