A common symptom of pharyngitis is swelling of the anterior cervical lymph nodes. why might lymph nodes swell in the presence of an infection? what else may cause swollen lymph nodes

Lymph is the fluid carrying the white blood cells. It protects the body against many infections. Lymph nodes are the small areas throughout the body and abundantly present in the neck, arm pits and groin areas. They contain the lymphocytes that fight infections. These nodes filter out harmful organisms and abnormal cells before the lymph reaches the blood. A swollen lymph node is an indication of an infection. It can be a minor infection like the ear infection, strep infection or serious medical problems like the lymphomas, other cancers and AIDS. During pharyngitis which is the inflammation of the pharynx, the lymph nodes swell with the T lymphocytes due to the immune response.