What is the function of surfactant?

Pulmonary Surfactant:

Function:

1. Reduction of Surface Tension: Surfactant reduces the surface tension at the air-liquid interface in the lungs' alveoli. By doing so, it helps to maintain alveolar stability during respiration. Without surfactant, the alveoli would collapse at the end of each exhalation due to the high surface tension of water, making breathing impossible.

2. Enhances Lung Compliance: Surfactant improves the elasticity and compliance of the lungs, reducing the work of breathing. It allows the alveoli to expand and recoil more easily during respiration.

3. Protection Against Atelectasis: Surfactant prevents the collapse of alveoli, especially during expiration. It helps keep the alveoli open, preventing atelectasis, a condition in which the alveoli collapse and become airless.

4. Immunological Defense: Surfactant contains various proteins and lipids that play a role in the innate immune defense of the lungs. These substances can interact with pathogens, bacteria, and viruses, enhancing the clearance of foreign particles from the airways.

5. Role in Gas Exchange: Surfactant may indirectly contribute to efficient gas exchange by facilitating alveolar stability and reducing the work of breathing. Proper functioning of the surfactant system ensures optimal oxygen uptake and carbon dioxide removal.

6. Neonatal Respiratory Distress Syndrome (NRDS): Surfactant is particularly crucial in newborn babies, especially premature infants. NRDS is a respiratory condition that occurs when there is a deficiency or dysfunction of surfactant in the lungs of premature babies. This leads to respiratory distress and can be life-threatening. Therefore, surfactant replacement therapy is often used to support breathing in these infants.

Overall, surfactant plays a critical role in maintaining the structural integrity of the lungs, promoting efficient lung function, and enhancing respiratory mechanics, thus ensuring proper gas exchange during respiration.