What is the primary significance of surfactant in the alveoli?

• A. Aiding in oxygen transport
• B. Reducing surface tension and preventing alveolar collapse
• C. Promoting alveolar inflammation
• D. Enhancing gas exchange efficiency

Answer: (B)

Surfactant plays a crucial role in the alveoli by reducing surface tension, which is vital for their proper function. Alveoli are tiny air sacs in the lungs where gas exchange occurs, and they must remain open to effectively exchange oxygen and carbon dioxide. When surfactant is present, it interacts with the water molecules lining the alveoli, decreasing the surface tension that tends to make the alveoli collapse during exhalation. This reduction in surface tension enables alveoli to remain stable and inflated, promoting easier breathing and preventing conditions such as atelectasis, where parts of the lung collapse.

While oxygen transport and gas exchange efficiency are important functions of the respiratory system, they primarily rely on the structure and function of hemoglobin and the surface area of the alveoli rather than surfactant. Surfactant does not promote inflammation; rather, it is essential for maintaining the integrity of the alveolar structure and function.