What does the visceral pleura do?

The visceral pleura is a delicate serous membrane that closely adheres to the surface of the lungs. Its primary function is to line the lungs themselves, providing a protective covering while allowing for smooth movement during respiration. This layer plays a crucial role in maintaining the integrity of the pleural space, which is essential for proper lung expansion and contraction.

As the lungs expand and contract during breathing, the visceral pleura helps reduce friction between the lungs and the thoracic wall by allowing these two surfaces to glide over each other. This is vital for efficient respiratory function.

The other options, while related to respiratory health, do not accurately describe the role of the visceral pleura. For instance, it does not serve as a direct barrier to infections or toxins; rather, it functions more in the context of lung mechanics and pleural function. Additionally, the visceral pleura does not facilitate gas exchange itself; that is the role of the alveoli and pulmonary capillaries. Overall, the specific adherence to the lungs and lining of the pleural cavity is a defining aspect of the visceral pleura's function.