Lymph nodes are part of the lymph system, which carries lymph
fluid, nutrients, and waste material between the body tissues and the
bloodstream. The lymph system is also an important part of the immune
system, the body's defense system against disease.
The lymph nodes (sometimes called lymph glands) filter lymph fluid
as it flows through them, trapping bacteria, viruses, and other foreign
substances, which are then destroyed by special white blood cells called
lymphocytes. Lymph nodes may be found singly or in groups; they may be as small
as the head of a pin or as large as an olive. Groups of lymph nodes can be felt
in the neck, groin, and underarms. Many lymph nodes in the body can't be
When there is a problem in the body, the nearby lymph nodes may become swollen. For example, if a
person has a throat infection, the lymph nodes in the neck may swell and become
Sarah Marshall, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & C. Dale Mercer, MD, FRCSC, FACS - General Surgery
The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.