Slide DMS125 [palatine tonsil, human, H&E]. The tonsils (palatine, pharyngeal, and lingual) are incompletely encapsulated aggregates of lymphoid nodules that surround the entrance to the oral pharynx (tonsilar ring of Waldeyer). They are interposed in the path of both air borne and ingested pathogens. Not infrequently in young people they are reactive (enlarged) due to lymphocyte response to antigenic challenge. In the preantibiotic era surgical removal of chronically enlarged, inflammed tonsils wasalmost a routine office procedure. Why has this practice largely been discontinued? What types of epithelium characteristically cover the free surfaces of the palatine and pharyngeal tonsils. Which tonsil has well-developed "crypts" ? Which is referred to as "adenoids" when abnormaly enlarged? Observe the extensive diffuse and condensed aggregates of lymphoid tissue beneath the surface epithelium. Look for lymphoid nodules. The nodules are B cell domains, the internodular zones are T cell dominated. Tonsils typically have efferent but no afferent lymphatic vessels.