Clusters of lymphatic tissue found in the pharynx are called what?

• A. Tonsils
• B. Lymph nodes
• C. Spleen
• D. Appendix

Answer: (A)

Tonsils are clusters of lymphatic tissue in the pharynx that form Waldeyer’s ring, a protective ring at the entrance to the respiratory and digestive tracts. They include the pharyngeal, palatine, and lingual tonsils and act as the first line of immune defense, catching pathogens inhaled or swallowed and presenting them to lymphocytes to trigger a response. This local immune tissue helps coordinate responses at mucosal surfaces, producing antibodies where they’re most needed. Lymph nodes, by contrast, filter lymph carried in lymphatic vessels; the spleen filters blood; and the appendix is gut-associated tissue, not located in the pharynx.