Home > Patients & Visitors > Health Library > Lymph nodes
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 felt.
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 tender.
Cancer can spread through the lymph system.
Current as of: January 25, 2020
Author: Healthwise Staff
Medical Review:Sarah Marshall MD - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Elizabeth T. Russo MD - Internal Medicine
To learn more about Healthwise, visit Healthwise.org.
© 1995-2020 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.
You'll find Decision Points to help you answer questions about:
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups and pregnancy.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.