tonsils

A rounded mass of tissue, usually of a lymphoid nature.

Tonsil. (Thibodeau/Patton, 2002)

Two masses of tissue on either side of the throat. The tonsils, part of the lymphatic system, help defend the body against harmful microorganisms.

1. a small mass of lymphoid tissue, especially that found in close association with the mucous membrane of the throat; generally used alone to designate the palatine tonsil. Other structures referred to as tonsils are the cecal, lingual, esophageal, paraepiglottic, pharyngeal and tubal lymphoid aggregations.
2. a small mass of tissue.

• cecal t. — the accumulated mass of lymphoid tissue in the wall of cecum especially the proximal segment of the avian cecum.
• cerebellar t. — a rounded mass forming part of the cerebellum on its inferior surface.
• esophageal t. — large volume of lymphoid tissue in the caudal segment of the duck's esophagus.
• follicular t. — a tonsil bearing numerous invaginations of its surface epithelium (fossulae) each surrounded by lymphoid tissue to form a follicle, as in the palatine tonsils of cattle or the lingual tonsils of the horse.
• lingual t. — diffuse collection of lymphoid tissue near the tongue root of most mammals.
• palatine t. — see palatine tonsil.
• paraepiglottic t. — a collection of lymphoid tissue craniolateral to the epiglottic base.
• pharyngeal t. — a collection of lymphoid tissue in the roof of the nasopharynx in pigs.
• soft palate t. — lymphoid tissue within the soft palate; principal tonsils in pigs in which it forms twin smooth patches of mucosa.
• tubal t. — the lymphoid tissue clustered close to the pharyngeal orifice of the auditory tube.