Bronchial cilia. Coloured scanning electron micrograph (SEM) of a normal human bronchial epithelium, the mucus membrane lining the major airways of the lung. Clumps of hairlike cilia (greenpink) protrude from the tops of specialised epithelial cells (brown). Rhythmic movements of the cilia serve to move bacteria and other particles away from the gasexchanging parts of the lung and towards the throat, where they can be expelled. Magnification unknown.
