Topic summary
Motile cilia
Extracted from the Wikipedia article Cilium.
Motile cilia
Mammals also have motile cilia or secondary cilia that are usually present on a cell's surface in large numbers (multiciliate), and beat in coordinated metachronal waves. Multiciliated cells are found lining the respiratory tract where they function in mucociliary clearance sweeping mucus containing debris away from the lungs. Each cell in the respiratory epithelium has around 200 motile cilia.