What is the primary function of pleural fluid in respiration?

What is the primary function of pleural fluid in respiration?

• A. It assists in the exchange of gases.
• B. It washes out debris that gets into the lungs.
• C. It lubricates the chest wall and lungs to prevent friction.
• D. It maintains the correct pH in the lungs

Answer: (C)

Pleural fluid lines the space between the lung’s surface and the chest wall, providing lubrication so the two layers can slide past each other smoothly as you breathe. This reduces friction during expansion and contraction and helps keep the lungs moving in concert with the chest wall, aided by the slight surface tension that helps keep the lungs inflated. Gas exchange takes place in the alveoli, debris is cleared by the respiratory tract’s cleaning systems, and pH is regulated by blood buffers and CO2 removal—not by pleural fluid.

Pleural fluid lines the space between the lung’s surface and the chest wall, providing lubrication so the two layers can slide past each other smoothly as you breathe. This reduces friction during expansion and contraction and helps keep the lungs moving in concert with the chest wall, aided by the slight surface tension that helps keep the lungs inflated. Gas exchange takes place in the alveoli, debris is cleared by the respiratory tract’s cleaning systems, and pH is regulated by blood buffers and CO2 removal—not by pleural fluid.