Caption

Lung lining. Coloured Scanning Electron Micrograph (SEM) of the surface of the internal lining of the human lungs. Also known as bronchial epithelium, this lining helps to keep the lungs free of infection. Clumps of fine hairs, called cilia (green) are seen. These protrude from between the tops of specialised epithelial cells (red). Rhythmic movements of the cilia move bacteria & other particles away from the gas- exchanging parts of the lungs, towards the throat where they can be swallowed or coughed up. Magnification: x4800 at 7x6cm size.