Final answer:
Pleural fluid functions to reduce friction during breathing and aids the lungs in expansion by creating surface tension. It also separates major organs and helps to prevent the spread of infection.
Step-by-step explanation:
Functions of Pleural Fluid
The pleural fluid serves several critical functions in the respiratory system. One of its primary roles is to reduce friction between the pleural layers as they rub against each other during the process of breathing. This lubrication is vital to prevent trauma that could be caused by the movement of the lungs. Additionally, pleural fluid contributes to the surface tension between the lungs and the thoracic wall, supporting the lungs' ability to expand upon inhalation. The adherence created by the pleural fluid ensures that the lungs follow the thoracic wall movement during ventilation. Furthermore, the fluid plays a role in separating major organs, providing a barrier that helps prevent movement interference and the spread of infections.