Article
Article
Tonsil
Article By:
Snook, Theodore Department of Anatomy, School of Medicine, University of North Dakota, Grand Forks, North Dakota.
Last reviewed:January 2021
DOI:https://doi.org/10.1036/1097-8542.700300
Localized aggregation of diffuse and nodular lymphoid tissue found in the region where the nasal and oral cavities open into the pharynx. The lymphoid tissue consists of small, closely packed round cells called lymphocytes supported in a specialized connective tissue framework called reticular tissue. When lymphocyte production is active, rounded and more densely packed clusters or nodules of these cells appear in the diffuse lymphoid tissue. The most active nodules possess lighter staining centers composed of somewhat larger, less densely packed lymphocytes showing evidence of cell division. Such areas are called germinal centers. In the tonsillar regions, the lymphoid tissue lies just beneath the lining epithelium. The tonsils are important sources of blood lymphocytes. They often become inflamed and enlarged, necessitating surgical removal.
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