What are the structures called that help in moving fluid along the epithelial lining of the lungs?

Cilia are hair-like structures that extend from the surface of epithelial cells, particularly in the respiratory tract. Their primary function is to move fluid and mucus along the epithelial lining of the lungs, which is essential for clearing out debris, pathogens, and excess mucus. This coordinated movement helps maintain a clear airway and contributes to respiratory health.

Microvilli, while also found on epithelial cells, primarily serve to increase surface area for absorption rather than for moving fluid. Flagella are long, whip-like structures that are primarily used for locomotion in certain cells, such as sperm cells, and are not involved in the movement of fluid along epithelial linings. Filopodia are slender projections that help with cell movement and sensing the environment, but they do not play a role in moving fluids along epithelial surfaces. Thus, cilia are the specialized structures responsible for this function in the lungs.