Epithelial cells are adapted to cover internal and external body surfaces.Squamous epithelium is made of squamous epithelial cells. It is made of thin, flat cells with a 'pavement-like' appearance.The epithelium is only one-cell thick so enables rapid diffusion across surfaces such as the lungs and capillaries.Ciliated epithelium is made of columns of ciliated epithelial cells.These have hair-like structures on the surface called cilia. Cilia are able to move in a rhythmic manner and waft substances along.Ciliated epithelium lines the trachea. Goblet cells are part of the epithelial tissue and secrete mucus to trap unwanted particles.