What is the primary component of pulmonary surfactant?

The primary component of pulmonary surfactant is a mix of phospholipids and proteins. Surfactant plays a crucial role in the respiratory system by reducing the surface tension of the fluid lining the alveoli, which prevents the collapse of these tiny air sacs during exhalation. The most abundant phospholipid in pulmonary surfactant is dipalmitoylphosphatidylcholine (DPPC), which is vital for its surface-active properties.

In addition to phospholipids, surfactant also contains specific proteins, primarily surfactant proteins A, B, C, and D, which are essential for its function and stability. These proteins participate in the regulation of surfactant homeostasis and play roles in innate immunity within the lungs.

The presence of both types of molecules makes phospholipids and proteins the correct and primary components of pulmonary surfactant, crucial for maintaining optimal lung function and gas exchange.