How do the diaphragm and intercostal muscles assist in breathing?

The diaphragm and intercostal muscles play crucial roles in the mechanics of breathing, primarily through their contraction, which aids in establishing negative pressure within the thoracic cavity. When the diaphragm contracts, it moves downward, and the intercostal muscles contract to elevate the ribs. This expansion of the thoracic cavity increases the volume inside it, thereby decreasing the pressure relative to the atmospheric pressure. As a result, air flows into the lungs, allowing for inhalation to occur.

This process establishes the essential negative pressure that facilitates airflow into the lungs, making the response regarding contraction leading to negative pressure correct. Understanding respiratory mechanics emphasizes the importance of muscular action in creating the necessary conditions for effective breathing.