Final answer:
The chemical that lowers lung surface tension and increases lung compliance is surfactant, which functions like a detergent to reduce the effort needed for lung inflation and prevent alveoli collapse.
Step-by-step explanation:
The chemical that lowers surface tension and therefore increases the compliance of the lungs is called surfactant. This substance works similarly to a detergent, which makes the inflation of the airways easier. When surfactant is applied to the airway tissues, it reduces the work necessary to inflate the airways, leading to increased lung volume and decreased work of breathing. Especially in premature infants who may not produce enough surfactant, this can be critical to prevent respiratory distress syndrome. Surfactant is also integral in maintaining the balance between small and large alveoli by reducing surface tension preferentially in smaller spaces, which prevents small alveoli from collapsing.
Resistance created by inelastic surfaces and airway diameters can reduce the flow of gases, and high compliance (due to the ability of the lungs to stretch) ensures a greater potential volume and consequential lower air pressure within the lungs, which is crucial for effective breathing.