Medical Terms for Major Pathology & Diagnostics of the Immune System

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  • 0:05 The Immune System
  • 0:34 Allergic Reactions
  • 2:42 Autoimmunity and…
  • 5:13 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

You have a pretty good internal police force in your body known as the immune system. And just like a police force, sometimes our immune systems can do things they're not supposed to. Find out what can go wrong in this lesson.

The Immune System

Your immune system is like an internal police force that is tasked with serving and protecting your body from things like bacteria and viruses. Unfortunately, it isn't perfect.

We all know that the police sometimes overreact or sometimes there aren't enough troopers to serve and protect the city. Well, sometimes the immune system also overreacts, or sometimes there aren't enough cells that make up the immune system around to protect your body. These problems have names that are related to the pathology of the immune system.

Allergic Reactions

So, we've all heard of cases where the police overreact to a situation. Something sets them off, like a previous experience of some sort that makes them become hyper-vigilant and hyper-sensitive the next time around, leading to an overreaction. Believe it or not, this happens with your immune system when a previous exposure to some sort of substance like pollen, or dust, or a drug causes it to become hyper-sensitive to that substance and to overreact to it upon subsequent exposure.

This is technically known as an allergy, an abnormally high sensitivity to certain substances acquired by exposure to said substance and brought to light upon re-exposure to it. Such a substance is called an allergen and the body's reaction to the allergen is known as an allergic reaction.

Many times, the allergic reaction is in response to something that is normally completely harmless to the body, like pollen, or even potentially beneficial, like food. There are two very general classes of allergic reactions. A localized allergic response occurs only when contact with the allergen is made. For instance, if you're walking in the woods and brush up against poison oak, you might get an itchy rash in that area of the skin.

The other general class is called a systemic, or body-wide, allergic reaction. The most severe of these is called anaphylaxis, an extreme reaction that affects a person's whole body and can kill them if not addressed right away. Anaphylaxis is often associated with drug reactions.

To help diagnose the cause of some allergic reactions, a scratch test can be employed. Here, the potential allergens are pricked into the skin's surface at different spots. Swelling and itching in the area of a particular allergen indicate an allergic reaction to it. The swelling and itching are caused by a compound called histamine that's produced by your immune system. And so, a very important class of medications that are used to try and counter the effects of histamine are easily enough called antihistamines.

Autoimmunity & Immunodeficiency

While the police may overreact in some instances, in other, even thankfully, rarer times, they may actually go out and purposefully harm the civilian population. It's happened, unfortunately. The immune system may purposefully try to harm the person's own body as well. There are many such disorders and they're collectively called autoimmune disorders, conditions where the immune system produces antibodies against itself. 'Auto-' means 'self.'

These antibodies are like little bullets or tags. That's because sometimes they destroy the person's cells themselves and other times, they tag a cell for destruction by other cells of the immune system. Examples of autoimmune disorders include myasthenia gravis, systemic lupus erythematous, and type 1 diabetes.

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