What is the name of serous membrane that covers thoracic cavity?
a) Myocardium
b) Pericardium
c) Pleura
d) Lining membrane
The correct answer and explanation is :
The correct answer is:
c) Pleura
Explanation:
The pleura is a serous membrane that lines the thoracic cavity and surrounds the lungs. It consists of two layers: the parietal pleura and the visceral pleura.
- Parietal Pleura: This is the outer layer that lines the inner surface of the thoracic wall, the diaphragm, and the mediastinum. It is in direct contact with the chest cavity’s interior.
- Visceral Pleura: This inner layer is directly attached to the surface of the lungs, covering them. It also folds over to become the parietal pleura as it continues around the thoracic cavity.
Between these two layers is the pleural cavity, which contains a small amount of pleural fluid. This fluid acts as a lubricant, allowing the lungs to expand and contract smoothly during breathing.
Functions of the Pleura:
- Protection: The pleura acts as a protective layer for the lungs, preventing damage from external friction as the lungs expand and contract with each breath.
- Reduction of Friction: The pleural fluid inside the pleural cavity reduces friction between the parietal and visceral layers, ensuring that the lungs move smoothly against the chest wall during respiration.
- Facilitates Breathing: The pleura’s ability to create a sealed environment around the lungs aids in maintaining negative pressure, which is crucial for lung expansion during inhalation and for keeping the lungs properly inflated.
Why the Other Options Are Incorrect:
- a) Myocardium: The myocardium is the muscular layer of the heart, not a serous membrane. It is responsible for the heart’s contractile function.
- b) Pericardium: The pericardium is a serous membrane that surrounds the heart, not the thoracic cavity. It has two layers: the fibrous pericardium (outer layer) and the serous pericardium (inner layer).
- d) Lining membrane: This term is too general and does not specifically refer to the pleura, pericardium, or any other specific membrane.