Question

State one function of pleural fluid.

Answer 1

Hint: Pleural fluid is found between the layers of pleura. Pleura are the membranes which line the thoracic cavity and surround the lungs. The space containing the fluid is called a pleural cavity. The pleural fluid consists of a small amount of a thin serous fluid which does an important role and aids in breathing.

Complete Explanation:
The pleural fluid has an important function that is to act as a lubricant during breathing. It is a thin translucent fluid that fills the cavity between the parietal or outer and visceral or inner pleural layers surrounding the lungs. The volume of fluid in a healthy lung is about \[5 - 10{\text{ }}ml\].
It lubricates the space between the pleura, allowing the pleura to function smoothly during inhalation and exhalation. It acts as a cushion for the delicate lung tissues against friction from the ribs and the chest wall.
The pleural fluid is produced and reabsorbed continuously. The mesothelial cells of the pleura regulate the composition and volume of the fluid.
Excess amount of pleural may have deteriorating effects such as chest pain and shortness of breath. This condition is called pleural effusion. Pleural effusion is triggered by many ill conditions. To find out the underlying cause, pleural fluid will be collected from the lungs and analysed.

Note:
There are two types of pleural fluid namely the transudate and the exudate. Transudate pleural fluid is a thin and clear fluid. It is produced during ill conditions such as congestive heart failure, Liver cirrhosis, pulmonary emboli etc. Exudate is a thicker pus-like fluid seen during conditions such as pneumonia, cancer and autoimmune diseases.