Decades ago, before the role of the tonsils and adenoids was better understood, it was typical after repeated bouts with tonsillitis to have a tonsillectomy and adenoidectomy. Today it is understood that the tonsils and adenoids are lymphoid tissues that:__

They are lymphoid tissues that filter bacteria from tissue fluid.

Explanation:

Both Tonsils and Adenoids are lymphatic tissues located with in the oral cavity in the form of Waldeyer rings. Adenoids are superior part of ring which is in the nasopharynx. Tonsils are referred to as palatine tonsils located on the posterolateral walls of oropharynx and are present on lateral side of Waldeyer rings. Both these lymphoid tissues are placed to filter bacteria coming from nasal and oral routes.