We have four sets of tonsils. There is a palatine tonsil either side of the back of the mouth. The lingual tonsil behind the tongue, and the tubal tonsils and adenoids on the roof of the mouth are part of the lymphatic system, a network of vessels used by the immune system to patrol and defend the body.
Together they form a defensive ring that guards the entrance to the lungs and digestive system. Inside the tonsils, powerful cells of the immune system can detect infection early, and mount a rapid response.
