Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Contraction of the diaphragm causes which action to take place?

1. Expiration

2. Inspiration

3. Digestion

4. Circulation

The correct answer is: Inspiration

The contraction of the diaphragm primarily facilitates the process of inspiration, which is the act of breathing in. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity. This increase in volume leads to a decrease in pressure within the lungs relative to atmospheric pressure, allowing air to flow into the lungs. As a result, oxygen is drawn in from the environment to be exchanged for carbon dioxide in the bloodstream. Inspiration is a vital part of the respiratory cycle and is essential for delivering oxygen to the body, which is needed for cellular respiration and overall metabolic processes. The diaphragm's movement is crucial in this process, making it the primary muscle of inhalation. The other options involve different physiological processes: expiration is the act of exhaling, digestion pertains to food processing in the gastrointestinal tract, and circulation relates to the movement of blood throughout the body.