A 12-Year-Old Girl Was Brought to the Hospital with a History

A 12-year-old girl was brought to the hospital with a history of fever, malaise, anorexia, and a sore throat. She also had hoarseness, a cough, and rhinitis. On examination there was erythema of the posterior pharyngeal wall, with small ulcers on the palatoglossal folds and soft palate. The tonsils were seen to be red and enlarged, and an obvious white-yellow exudate was seen on the surface of the left tonsil. Examination of the deep cervical lymph nodes showed enlargement and tenderness of the node below and behind the angle of the mandible; the enlargement was greatest on the left side. A diagnosis of viral pharyngitis was made. List the various lymphoid organs found in the nasal and oral parts of the pharynx. Explain Waldeyer's ring.