The tissue, which forms covering or lining is known as epithelial tissue, eg, Squamous epithelium, columnar epithelium and ciliated epithelium etc. Lining of intestine and kidney in human is formed by columnar epithelium which has cells with microvilli on free surface and forms brush border. Brush border surface increases the absorptive area of the surface. Ciliated epithelium is modified columnar epithelium, cilia present on free surface, eg. lining of oviduct. Keratinized compound epithelium is present epidermis of skin, hairs.