Slide #DMS 124 [Pharyngeal tonsil, human, H&E]. Note the pseudostratified columnar epithelium on the lower aspect of this specimen that marks it as part of the respiratory system.

This is a very low power view of a section through pharyngeal tonsil. This tonsil typically lacks the deep tonsillar crypts seen in the palatine tonsil, and in the absence of metaplastic change, is covered by respiratory epithelium. Note the abundance of large, secondary lymphoid follicles in the tissue beneath the epithelial surface.

At higher power, this rather faded section reveals the ciliated, respiratory epithelium of the pharyngeal tonsil, beneath which is an abundance of both diffuse and nodular lymphoid tissue. Note that the cilia are often not visible.