Final answer:
Surfactant on the respiratory membrane reduces surface tension within the alveoli, aiding in lung inflation and preventing collapse of the alveoli. It plays a crucial role in maintaining lung stability for efficient gas exchange. Premature babies often lack sufficient surfactant, causing respiratory distress syndrome.
Step-by-step explanation:
The function of the thin film of surfactant on the respiratory membrane is fundamental to proper lung function. Surfactant serves primarily to reduce surface tension at the air-tissue interface within the alveoli. By doing so, it lowers the work needed to inflate the airways, making it easier for the lungs to expand during inhalation. Additionally, surfactant helps to maintain the stability of alveoli by preventing the collapse of smaller alveoli and ensuring they don't empty their air into larger ones, which would lead to uneven ventilation and potential lung damage. Consequently, this property is critical for efficient gas exchange and overall respiratory health. In newborns, particularly those born prematurely, insufficient production of surfactant can lead to respiratory distress syndrome due to the increased effort required to inflate the lungs.
The respiratory membrane, which is formed by type I alveolar cells and capillary membranes, facilitates gas exchange through its thin barrier (approximately 0.5 µm thick) by simple diffusion of gases like oxygen and carbon dioxide between the blood and the air within the lungs.