Pleura (Thoracic Pleura): Structure, Function & Diseases

The pleura, or pleura, is a thin skin that lines the inside of the chest cavity and covers the surfaces of the lungs. The name is derived from the Greek for flank or rib. Keeping the heart, chest wall and lungs from sticking together is the job of the pleura.

What is the pleura?

The pleura is a shifting gap that lies between the chest wall and the lungs. This gap contains fluid. The lungs follow movements of the chest wall and diaphragm due to a negative pressure in the pleural gap and the two pleural blades. This is how the musculature allows breathing movements. The pleura consists of two leaves. While the outer leaf is fused to the rib cage, the inner leaf lies directly on the lung and is likewise fused to the same. Between them are only a few millimeters, the so-called pleural gap. The pleural space is filled with serous, i.e. low-protein, fluid and lies between the lung pleura and the pleura. It provides smooth movement of both lungs and assists the lungs in moving the chest wall.

Anatomy and structure

The pleura, consisting of the lung pleura and the pleura, divides into the pleural domes, the pleura, the area around the connective tissue of the mediastinum, and the top of the diaphragm. The pleural sheets of the pleura secrete a fluid to keep the lungs slidable. The pleura covers the entire lung with the thin skin. To maintain supply, the inner area periodically requires a certain amount of empty space. This creates a negative pressure that expands the lungs during inhalation. This causes the ribs to rise and the diaphragm to lower. During exhalation, the ribs lowered and the diaphragm rises. The lungs contract again and the air is forced out.

Function and tasks

The pleura has many sensitive nerves, which accounts for the painfulness in case of inflammation of the pleura. The task of the pleura is to ensure that the lungs, chest wall and heart do not stick together. Due to the lining of the chest cavity by the pleura, the pleura acts as a layer between the lungs and the wall of the chest cavity, which can be displaced. In this way, it supports the development of the lungs. Due to the smooth surface of the pleura and the secretion of fluid, the lungs slide smoothly during inhalation and exhalation. Immediate medical attention is needed for severe complications such as a tension pneumothorax. In a tension pneumothorax, air enters the chest cavity from the outside through a hole in the pleura, but the air cannot escape. The chest continues to inflate with air, ending with rapid lung compression and severe breathing difficulties.

Diseases and symptoms

The pleura may become inflamed if it becomes diseased. If there is a roughening of the pleura or if the two pleural sheets stick together, breathing difficulties are the result. In a dry form of pleurisy, when the pleura is inflamed, there is no pleural effusion, but in the wet form there is. Inflammation of the pleura usually accompanies a disease such as pneumonia, pulmonary infarction or lung cancer. A pleural effusion may be a symptom of other diseases. Puncture of the effusion in the pleura is often done to remove the fluid. This gives patients relief and subsides the pain in the pleura. Severe pain, shallow breathing, and elevated temperature with an irritable cough may be other symptoms. A lung x-ray is required to confirm the diagnosis. There is marked respiratory impairment and discomfort during breathing. As a result of a pneuomthorax, air enters the narrow pleural space caused by a ruptured alveoli or external injury. The lung collapses to a minimal volume and gas exchange no longer occurs. A pneumothorax results. If the pleura becomes inflamed, dangerous complications such as pleural effusion can occur. In this case, bacterial pneumonia spreads. After operations in the chest cavity or in the case of a lung abscess, a pleural empyema, a purulent effusion, can occur. Patients have a high fever and cough. Night sweats occur and there is weight loss. Diagnosis is made by puncturing the pleura. Another complication following inflammation of the pleura is fusion of both pleural sheets. The pleural rind is thick and immobile.It can be several centimeters thick and tends to shrink, interfering with the necessary unfolding of the lungs for breathing. Most malignant tumors in the pleura are metastases from other malignant tumors that originated elsewhere. Most commonly, lung, breast, or gastrointestinal tract tumors are involved and form metastases that spread to the pleura.