<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Respiratory epithelium is a type of ciliated epithelium found lining most of the respiratory tract, where it serves to moisten and protect the airways . It is not present in the larynx and pharynx . It also functions as a barrier to potential pathogens and foreign particles, preventing infection and tissue injury by the action of mucociliary clearance . </P> <P> The respiratory epithelium lining the upper respiratory airways is classified as ciliated pseudostratified columnar epithelium . This designation is due to the arrangement of the multiple cell types composing the respiratory epithelium . While all cells make contact with the basement membrane and are, therefore, a single layer of cells, the nuclei are not aligned in the same plane . Hence, it appears as though several layers of cells are present and the epithelium is called pseudostratified . </P>

Where are ciliated cells found in the respiratory system