What term refers to the thin membranes that cover the lungs and chest wall?

The term that refers to the thin membranes covering the lungs and chest wall is "pleura." This is a crucial structure in the respiratory system, consisting of two layers: the visceral pleura, which is attached to the surface of the lungs, and the parietal pleura, which lines the chest cavity. The space between these two layers, known as the pleural cavity, contains pleural fluid that reduces friction during breathing and helps maintain pressure, allowing the lungs to expand and contract effectively. This anatomical feature is vital for respiratory mechanics and the overall function of the lungs.

The incorrect options include alveoli, which are tiny air sacs in the lungs where gas exchange occurs, and bronchi, which are the main passageways that branch from the trachea into the lungs. The trachea itself is the windpipe that connects the throat to the bronchi. While all these components are essential for respiratory function, none serve the specific role of covering the lungs and chest wall like the pleura does.