Font Size
A
A
A

Immune System


Picture of immune system

Illustration copyright 2000 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

The immune system is the body's natural defense system that helps fight infections. The organs of the immune system include:

  • The tonsils, which are on either side of the throat at the back of the throat. The tonsils help make antibodies that fight infections.
  • Lymph nodes and lymphatics, which are found throughout the body. The lymphatics carry fluid, nutrients, and waste material between the body tissues and the bloodstream. The lymph nodes 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.
  • Thymus gland, which is found in the upper chest at the bottom of the neck, behind the breastbone. The thymus helps make antibodies that fight infection.
  • Bone marrow, which is found mainly inside the long bones, vertebrae, and pelvic bones of the body. The marrow makes white blood cells that destroy bacteria, viruses, and other organisms that cause infection.
  • Spleen, which is found in the upper left side of the abdomen. The spleen supports the immune system by helping it to recognize bacteria and other foreign substances and destroying them.
ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerW. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Last RevisedDecember 30, 2011

eMedicineHealth Medical Reference from Healthwise

This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

To learn more visit Healthwise.org

© 1995-2014 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.





Medical Dictionary