ALERT

For the latest coronavirus care instructions and resources, please call our COVID-19 hotline at 208-381-9500. Find additional information and resources here and learn more about how we're working to keep you healthy and safe.

toggle mobile menu Menu
toggle search menu

Site Navigation

Supplemental

Menu

Immune system

Location in body of parts of immune system, with detail of tonsils, thymus, bone marrow, spleen, and lymph nodes and vessels

The immune system is the body's natural defense system that helps fight infections. The immune system includes the following.

The tonsils.

These are on either side of the back of the throat. The tonsils help make antibodies.

The thymus gland.

This is found in the upper chest at the bottom of the neck, behind the breastbone. The thymus also helps make antibodies.

Bone marrow.

This is soft tissue that is found mainly inside the long bones of the arms and legs, the vertebrae, and the pelvic bones. The marrow makes white blood cells that destroy bacteria, viruses, and other organisms that cause infection.

The spleen.

This organ is found in the upper left side of the abdomen. It filters the blood by removing old or damaged blood cells and platelets. The spleen helps the immune system by destroying bacteria and other foreign substances.

Lymph nodes and vessels (the lymphatic system).

This system is found throughout the body. It carries fluid, nutrients, and waste material between the body tissues and the bloodstream. The lymph nodes filter lymph fluid as it flows through them. The nodes trap bacteria, viruses, and other foreign substances, which are then destroyed by special white blood cells. These cells are called lymphocytes.

Current as of: January 26, 2020

Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Elizabeth T. Russo MD - Internal Medicine

This information does not replace the advice of a doctor. Healthwise, Incorporated 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. Healthwise is a URAC accredited health web site content provider. Privacy Policy. How this information was developed to help you make better health decisions.

© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.