What is a pleural membrane?
The pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. The thin space is known as the pleural cavity and contains a small amount of pleural fluid (few milliliters in a normal human). The outer pleura is attached to the chest wall (1-9).
What is the function of the pleura?
The pleura includes two thin layers of tissue that protect and cushion the lungs. The inner layer (visceral pleura) wraps around the lungs and is stuck so tightly to the lungs that it cannot be peeled off. The outer layer (parietal pleura) lines the inside of the chest wall.
How the pleura normally work to keep the lung open and inflated?
The pleural cavity always maintains a negative pressure. During inspiration, its volume expands, and the intrapleural pressure drops. This pressure drop decreases the intrapulmonary pressure as well, expanding the lungs and pulling more air into them.
What is pleural linkage?
PLEURAL LINKAGE: between the lungs and the ribs; it enables the lungs to expand and contract as the thorax changes volume. COSTAL (or parietal) PLEURA: A membrane that lines the rib cage. PULMONARY (or visceral) PLEURA: A membrane that covers the lungs.
What are pleural reflections?
The lines along which the parietal pleura changes direction as it passes from one wall of the pleural cavity to another are called the lines of pleural reflection. The lines of pleural reflection are formed by the parietal pleura as it changes direction (reflects) from one wall of the pleural cavity to another.
What is the relationship between inspiration and expiration?
Inspiration occurs when lung pressure is decreased below atmospheric pressure, and that causes the air to move into the lungs. Expiration, on the other hand, occurs when lung pressure is increased above atmospheric pressure, and that pushes the air out of the lungs.
What does the pleural membrane cover?
The pleural membrane is thin, moist, slippery and has two layers. The outer, or parietal, pleura lines the inside of the rib cage and the diaphragm while the inner, visceral or pulmonary, layer covers the lungs. Between the two layers is the intrapleural space, which normally contains fluid secreted by the membranes.
What is the fundamental importance of pleural linkage in the respiratory system?
Function. The pleural cavity, with its associated pleurae, aids optimal functioning of the lungs during breathing. The pleural cavity also contains pleural fluid, which acts as a lubricant and allows the pleurae to slide effortlessly against each other during respiratory movements.
What are the surface markings of the pleura?
The surface markings of the lines of pleural reflection are important to know as an incision or puncture along these lines can inadvertently cause a pneumothorax or a hemothorax. The lungs do not completely fill the anterior and posterior regions of pleural cavities resulting in the formation of pleural recesses.
Is the parietal pleura part of the visceral membrane?
The visceral pleura is the thin, slippery membrane that covers the surface of the lungs and dips into the areas separating the different lobes of the lungs (called the hilum ). The parietal pleura is the outer membrane that lines the inner chest wall and diaphragm (the muscle separating the chest and abdominal cavities).
What makes up the lining of the pleural cavity?
The pleural cavity is lined by a fibrous mesothelial membrane that is made up of a parietal and visceral layer. The parietal layer is the lining of the internal thoracic cavity, and the visceral layer covers the outside of the lungs.
Is the pleura the only membrane around the heart?
The pleura is not the only set of membranes lining body cavities. There is a membrane around the heart (pericardium) and a membrane lining the abdominal cavity (peritoneum) as well.