<unk>  is a type of epithelium found lining the upper and lower<unk>  tracts, where it serves to moisten and protect the airways. It also functions as a barrier to potential pathogens and foreign objects, preventing infection by action of the ciliary escalator.
Respiratory epithelium
Epithelium
Olfactory epithelium
Junctional epithelium
Nervous tissue
Muscles of larynx
Mucous membrane of nose
Neuroepithelial cell