The human palatine tonsils and the nasopharyngeal tonsil are lymphoepithelial tissues located in strategic areas of the oropharynx and nasopharynx, although most commonly - the term "tonsils" refers to the palatine tonsils [that can be seen in the back of the throat]. These immunocompetent tissues represent the defense mechanism of first line against ingested or inhaled foreign pathogens. However, the fundamental immunological roles of tonsils have yet to be addressed.
Like other organs of the lymphatic system, some believe them to be involved in helping fight off pharyngeal and upper respiratory tract infections, but there is no conclusive evidence to that effect.
An inflammation of the tonsils is called tonsillitis.