The tonsils and adenoids are composed of tissues similar to the lymph nodes or glands found in the neck or other parts of the body. Together, they are part of a ring of glandular tissue (Waldeyer's ring) encircling the back of the throat.The tonsils are the two masses of tissue on either side of the back of the throat. Tonsils and adenoids are composed of tissues similar to the lymph nodes or glands. 2  Acute tonsillitis is an infection of the tonsils caused by one of several types of bacteria or viruses.