What primarily determines airflow in the respiratory system?

Airflow in the respiratory system is primarily determined by the relationship between pressure differences and resistance within the airways. The principles of gas flow dictate that air moves from an area of higher pressure to an area of lower pressure. This pressure gradient is crucial for inhalation and exhalation.

Resistance is influenced by the diameter and patency of the airways; when airway resistance increases—due to factors such as bronchoconstriction or mucus buildup—less airflow occurs for a given pressure gradient. Conversely, when resistance decreases, airflow increases.

Understanding airflow dynamics also requires acknowledging that compliance—how easily the lungs can expand—is involved, but is secondary to the interplay of pressure and resistance in dictating airflow. Thus, recognizing these fundamental physiological principles highlights why pressure and resistance are the primary determinants of airflow in the respiratory system.