Light micrograph of respiratory epithelium with cilia. The respiratory epithelial cells are columnar (elongated arranged vertically towards the top of the picture) and have a layer of cilia at their surface. The cilia are filamentous or ?œhair like??structures which function to trap and expel foreign particles which may enter the respiratory tract. The columnar cells have nuclei (dark blue elongated structures) and sit atop a basement membrane (bright pink horizontal line). Beneath the basement membrane are cells of the lamina propria (lighter pink with scattered blue fibroblast nuclei). Haematoxylin and eosin stained tissue section. Magnification: 600x when printed at 10 centimetres.