to the left shows a model of pseudostratified columnar epithelium. This type
of tissue consists of a single layer of cells resting on a noncellular
basement membrane that secures the epithelium. The tissue appears stratified
(occurring in several layers) because the cells are not all the same height and because their nuclei
(shown as black oval structures) are located at different levels. Pseudostratified
ciliated columnar epithelium lines the trachea (windpipe) and larger respiratory passage ways.