These are 2 of the lymphoid tissues in Waldeyer's ring (including adenoids or vault tonsils, tonsils or palatine tonsils, eustachian tonsils, and lingual tonsils) that are responsible for recognizing bacteria and creating antibodies to destroy them when they re-invade. Because of their important role in the development of the immune system, adenoidectomy and tonsillectomy should not be performed indiscriminately.