The ultrastructure of rat laryngeal epithelia.

The histology and ultrastructure of the rat laryngeal epithelia are described. Five epithelial types were identified. Stratified squamous epithelium was found over most of the epiglottis, arytenoid projections and lateral ventricles. The vocal folds were covered by a low squamoid type of epithelium. Respiratory epithelium, similar to that found elsewhere in the respiratory tract, occupied all the mucosa caudal to the vocal folds, small areas at the base of the epiglottis and along the inner aspects of the arytenoid projections. Two forms of relatively unusual pseudostratified cuboidal epithelium were present in the ventrolateral aspect at the level of the arytenoid projections and within the ventral pouch. Non-myelinated, intro-epithelial nerve fibres were found throughout the larynx, and were abundant in areas at the base of the epiblottis covered by respiratory epithelium and to a lesser extent in the cuboidal epithelium of the ventral pouch. Globule leucocytes were frequently found within respiratory epithelium, less frequently in cuboidal epithelium and only rarely in squamous areas.