glenn ellis

Glenn Ellis

*The human body is constantly engaged in a bitter internal war against vast armies of microscopic enemies.

Pathogens – be they bacteria, parasites, fungi or viruses – will seek any means possible to broach our bodies’ defenses; they will enter through wounds, or through the mouth as we swallow, or even when we breathe in.

Once inside our bodies, they do their utmost to grow and multiply – with destructive consequences. By damaging our cells or releasing their poisons, these pathogens cause a host of illnesses, from common colds and measles to potentially fatal conditions like tuberculosis and malaria.

Thankfully for us, we are equipped with an internal defense mechanism designed to combat these threats: the immune system. This extraordinarily sophisticated set up enlists the help of a complex network of organs, tissues and cells. However, its purpose is remarkably simple: to recognize, disable and dispose of all intruders – and then to remember them, in case they return at a later date.

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 the power of the immune system, 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 your immune 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 immune system is working, but the moment your immune system 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 immune 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 of it are understood and new drugs come on the market — knowing about the immune system 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 our immune system 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. Here are several examples:

  • When you get a cut, all sorts of      bacteria and viruses enter your body through the      break in the skin. When you get a splinter you also have the sliver of      wood as a foreign object inside your body. Your immune system responds and      eliminates the invaders while the skin heals itself and seals the      puncture. In rare cases the immune system misses something and the cut      gets infected. It gets inflamed and will often fill with pus. Inflammation      and pus are both side-effects of the immune system doing its job.
  • When a mosquito bites you, you get a red,      itchy bump. That too is a visible sign of your immune system at work.
  • 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 immune system and you catch a cold, get the flu or worse. A cold      or flu is a visible sign that your immune 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 your immune system 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      immune system: vomiting and diarrhea are two of the most common symptoms.
  • There are also all kinds of      human ailments that are caused by the immune 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      immune system inappropriately attacking cells in the pancreas and      destroying them. Some people have rheumatoid arthritis, which is caused by      the immune system acting inappropriately in the joints. In many different      diseases, the cause is actually an immune system error.
  • Finally,      we sometimes see the immune system because it prevents us from doing      things that would be otherwise beneficial. For example, organ transplants are much harder      than they should be because the immune system often rejects the      transplanted organ. When the foreign tissue is placed inside your body,      its cells do not contain the correct identification. Your immune system      therefore attacks the tissue. The problem cannot be prevented, but can be      diminished by carefully matching the tissue donor with the recipient and      by using immunosuppressing drugs to try to prevent an immune system      reaction. Of course, by suppressing the immune system these drugs open the      patient to what are known as opportunistic infections.

Sometimes the immune system makes a mistake. One type of mistake is called autoimmunity: the immune system for some reason attacks your own body in the same way it would normally attack a germ. Two common diseases are caused by immune system mistakes. Juvenile-onset diabetes is caused by the immune system attacking and eliminating the cells in the pancreas that produce insulin. Rheumatoid arthritis is caused by the immune system attacking tissues inside the joints.

Allergies are another form of immune system error. For some reason, in people with allergies, the immune system strongly reacts to an allergen that should be ignored. The allergen might be a certain food, or a certain type of pollen, or a certain type of animal fur. This reaction is caused primarily by mast cells in the nasal passages. In reaction to the pollen the mast cells release histamine. Histamine has the effect of causing inflammation, which allows fluid to flow from blood vessels. Histamine also causes itching. To eliminate these symptoms the drug of choice is, of course, an antihistamine.

Take good care of yourself and live the best life possible!

The information included in this column is for educational purposes only. It is not intended nor implied to be a substitute for professional medical advice. The reader should always consult his or her healthcare provider to determine the appropriateness of the information for their own situation or if they have any questions regarding a medical condition or treatment plan.

Glenn Ellis, is a Health Advocacy Communications Specialist. He is the author of Which Doctor?, and Information is the Best Medicine. A health columnist and radio commentator who lectures, nationally and internationally on health related topics, Ellis is an active media contributor on Health Equity and Medical Ethics.

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