First Lady Michelle Obama shares tips on parenting with moms and other audience members in a WebMD Town Hall meeting in Miami, Florida.
Information and Resources
Components of the 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 immune system is made up of antibodies, white blood cells, and other chemicals and proteins that attack and destroy substances such as bacteria and viruses that they recognize as foreign and different from the body's normal healthy tissues. The immune system also includes:
- The tonsils and thymus, which make antibodies.
- The lymph nodes and vessels (the lymphatic system). This network of lymph nodes and vessels throughout the body carries lymph fluid, nutrients, and waste material between the body tissues and the bloodstream. The lymphatic system is an important part of the immune system. 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.
- Bone marrow. This is soft tissue found mainly inside the long bones, vertebrae, and pelvic bones of the body. It is made up of red marrow, which produces red and white blood cells and platelets, and yellow marrow, which contains fat and connective tissue and produces some white blood cells.
- The spleen, which filters the blood by removing old or damaged blood cells and platelets and helps the immune system by destroying bacteria and other foreign substances.
- White blood cells. These blood cells are made in the bone marrow and protect the body against infection. If an infection develops, white blood cells attack and destroy the bacteria, virus, or other organism causing it.
WebMD Medical Reference from Healthwise
Last Updated:
June 11, 2010
This information is not intended to replace the advice of a doctor.
Healthwise disclaims any liability for the decisions you make based on this
information.
© 1995-2011 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Top 12 Health Topics-
1.
-
2.
-
3.
-
4.
-
5.
-
6.
-
7.
-
8.
-
9.
-
10.
-
11.
-
12.
Top 12 Videos-
1.
-
2.
-
3.
-
4.
-
5.
-
6.
-
7.
-
8.
-
9.
-
10.
-
11.
-
12.
Hot Topics
- Which Drugstore Tooth Whiteners Work Best?
- Kids' Top 6 Worries and How to Fix Them
- Surprising Headache Triggers
- Safe Ways to Lose Weight Fast
- Counting Carbs When You Use Insulin
- Fibromyalgia: Symptoms and Treatments
- CML: How It Affects Your Body
- 6 Sex Mistakes Men Make
- Dupuytren's Contracture: What You Need to Know
- Symptoms of Vitamin B12 Deficiency
WebMD Video: Now Playing
FROM CBS NEWS
U.S. panel says men shouldn't get a PSA test
Panel found PSA test prevented only one death for every 1,000 men tested, but caused harmful side effects for up to 30 to 40 men for every 1,000 tested
More from CBS News:
Health Solutions From Our Sponsors
Advertise With Us|WebMD Corporate|Medscape Reference|eMedicineHealth|RxList|Medscape|MedicineNet|BootsWebMD
©2005-2012 WebMD, LLC. All rights reserved.
WebMD does not provide medical advice, diagnosis or treatment. See additional information.