Final answer:
Pulmonary surfactant is essential for reducing surface tension in the alveoli, preventing collapse during exhalation, increasing lung compliance, and reducing the work of breathing.
Step-by-step explanation:
Pulmonary surfactant has a critical role in maintaining lung function by reducing the surface tension at the air-tissue/water interface of the alveoli. This reduction in surface tension is essential as it helps to prevent the alveoli from collapsing. The surfactant works similarly to a detergent, however, its unique properties allow it to regulate wall tension during breathing cycles, which helps to maintain the stability of both large and small alveoli. Without sufficient surfactant, like in the case of premature babies, there can be increased work of breathing and a risk of respiratory distress syndrome.
Furthermore, by reducing surface tension, surfactant helps to increase lung compliance, allowing the lungs to stretch more easily and thereby reducing the energy needed to inflate the lungs during breathing. This translates into a decreased work of breathing, as the lungs can expand with less effort.