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Immune System: Introduction
Every day, your body is exposed to thousands of potential disease-causing organisms, or pathogens. These pathogens are everywhere, on your hands, in the air, even on your pillow! Thinking about how many pathogens are out there, it’s amazing that we don’t get sick more often. How does your body work to stay healthy with everyday exposure to these potential pathogens?
Your immune system! When your body fights a cold or an infection, it is your immune system at work. All animals, from fruit flies to humans, have some type of immune system to keep them healthy.
How does it work?
This ability for recognition is important because you don’t want these immune cells to attack your own body. When the immune system is not working the way it should and cannot identify (or “see”) the difference between self and what is non-self, disease results- this is called “auto immunity”. Auto immunity causes damage to the body’s organs and tissues.
Foreign “invaders” are usually bacteria, fungi, or viruses that may cause disease or infection. These microorganisms are all around us as a normal part of our environment, and only cause problems in certain situations, for example if your immune system is not working normally (immune suppression), if the microorganisms are too great in number, or if they are especially pathogenic (disease-causing).
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Editor: Carol Elland
NASA Official: B J Navarro
Last Updated: September 2006
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