How Your Immune System Works

Inside your body there is an amazing protectio­n mechanism called the immune system. It is designed to defend you against millions of bacteria, microbes, viruses, toxins and parasites that would love to invade your body. To understand its power all that you have to do is look at what happens to anything once it dies. That sounds gross, but it does show you something very important about the system.

When something dies, its immune system (along with everything else) shuts down. In a matter of hours, the body is invaded by all sorts of bacteria, microbes, parasites... None of these things are able to get in when your system is working, but the moment it stops the door is wide open. Once you die it only takes a few weeks for these organisms to completely dismantle your body and carry it away, until all that's left is a skeleton. Obviously your immune system is doing something amazing to keep all of that dismantling from happening when you are alive.

The system is complex, intricate and interesting. And there are at least two good reasons for you to know more about it. First, it is just plain fascinating to understand where things like fevers, hives, inflammation, etc., come from when they happen inside your own body. You also hear a lot about the immune system in the news as new parts are understood and new drugs come on the market -- knowing about it makes these news stories understandable.

Your immune system works around the clock in thousands of different ways, but it does its work largely unnoticed. One thing that causes us to really notice it is when it fails for some reason. We also notice it when it does something that has a side effect we can see or feel.

Each day you inhale thousands of germs (bacteria and viruses) that are floating in the air. Your immune system deals with all of them without a problem. Occasionally a germ gets past the system and you catch a cold, get the flu or worse. A cold or flu is a visible sign that your system failed to stop the germ. The fact that you get over the cold or flu is a visible sign that your immune system was able to eliminate the invader after learning about it. If it did nothing, you would never get over a cold or anything else.

Each day you also eat hundreds of germs, and again most of these die in the saliva or the acid of the stomach. Occasionally, however, one gets through and causes food poisoning. There is normally a very visible effect of this breach of the system: vomiting and diarrhea are two of the most common symptoms.

There are also all kinds of human ailments that are caused by the system working in unexpected or incorrect ways that cause problems. For example, some people have allergies. Allergies are really just the immune system overreacting to certain stimuli that other people don't react to at all. Some people have diabetes, which is caused by the system inappropriately attacking cells in the pancreas and destroying them. Some people have rheumatoid arthritis, which is caused by the system acting inappropriately in the joints. In many different diseases, the cause is actually a system error.

There are many immune system organs, so let's start learning about all of them.

Return from Immune System to Home Page