What is the role of the pleura in the respiratory system?

• A. To filter air
• B. To secrete mucus
• C. To facilitate lung movement during breathing
• D. To pump air into the lungs

Answer: (C)

The pleura play a crucial role in facilitating lung movement during breathing. This double-layered membrane surrounds each lung and covers the inner surface of the chest wall. The pleural space between these two layers contains a small amount of pleural fluid, which acts as a lubricant. This lubrication is vital because it reduces friction as the lungs expand and contract during respiration. When the diaphragm and intercostal muscles contract, creating a negative pressure within the pleura, the lungs are pulled outward, allowing for efficient inhalation. Conversely, during exhalation, the elasticity of the lungs coupled with this pleural mechanism aids in lung retraction. Therefore, the function of the pleura is essential for smooth and effective respiratory mechanics.