Which of the following is happening during a contraction of the diaphragm?

Question

Quizplus · Accepted Answer

When the diaphragm is contracting, it is moving downward and allowing the lungs to inflate. During inhalation, alveolar pressure is decreased because the expansion of the lungs increases the surface area or number of alveoli available for gas exchange, thus reducing the pressure at the alveoli.
Since air is being inhaled, the volume of air in the thoracic cavity is increased, not decreased.
Alveolar pressure increases during exhalation, because the lungs are slightly collapsing, reducing the surface area of the alveoli.
Forced expiration is not occurring during diaphragm contraction, because this indicates inhalation.

Which of the Following Is Happening During a Contraction of the Diaphragm