Autoimmune Diseases: Definitions & Types

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  • 0:01 Mistaken Identity
  • 0:34 What Is Autoimmune Disease?
  • 2:23 Types of Autoimmune Disease
  • 6:24 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

What is an autoimmune disease? Why does it occur? What are some examples of autoimmune diseases? This lesson will describe myasthenia gravis, multiple sclerosis, type 1 diabetes, and much more.

Mistaken Identity

Rarely, albeit not entirely uncommonly, we've all experienced a little case of mistaken identity. Maybe someone thinks we're someone else or you think that a stranger looks like your great aunt Myrna. It's innocent enough 99% of the time. Your body's defense system may also undergo cases of mistaken identity and it is equally rare. But when it does occur, it's not very innocent 99% of the time.

What Is Autoimmune Disease?

This mistaken identity is more appropriately called autoimmune disease, which is a process where a person's immune system attacks their own body. So, normally, your immune system is there to protect you like police, SWAT, or the military protect you. Our immune system uses all sorts of soldiers, weapons, and shields to go after the bad guys, like viruses and bacteria, and stop them from hurting us.

Admittedly, collateral damage does occur in this process a little bit. I mean, we've all heard of that very unfortunate incident where law enforcement may have accidentally hurt the victim instead of the perpetrator. But it's not like they targeted the innocent victim; it was just an accident. But in autoimmune disease everything is very much targeted and is anything but an accident. Your body's protective force actually targets your tissues, organs, and cells for destruction.

We don't know the full story of why it occurs, but there are many different possibilities. One is a case of mistaken identity. Sometimes things in our body have little markers on them, like tattoos on a person, that look very similar to the tattoo of a pathogen, or bad guy. So, our police force, thinking it's the bad guy all over again as a result of zeroing in only on that tattoo, springs into action and tries to destroy our body's cells that have the same-looking tattoo.

This destructive process leads to a lot of damage to the cells and tissues of our body, as you can only imagine, and results in a lot of diseases. Knowing this, we are now going to briefly discuss the many autoimmune diseases that fall in line with the theme of this destructive process.

Types of Autoimmune Disease

Systemic lupus erythematosus is an autoimmune disease that attacks the brain, kidneys, joints, skin, heart, and many other organs in the body. People with this problem sometimes have a characteristic 'malar rash' on their face.

Graves' disease and Hashimoto's disease are two autoimmune diseases that affect the thyroid gland. Graves' disease causes overproduction of the thyroid hormone, leading to eyeballs that bulge out of the head, which is called exophthalmos. On the flipside, Hashimoto's disease actually causes an underactive thyroid gland. This can lead to a feeling of fatigue because the thyroid hormone is like a power drink for your body.

Another autoimmune disease is myasthenia gravis, which is a disorder that results in the weakness of voluntary muscles. Voluntary muscles are the muscles that you can consciously control, like those of your hands and feet. Myasthenia gravis, literally 'grave muscle weakness,' occurs because your immune system blocks the signals for muscular movement from reaching the muscles themselves. This is like cutting a wire in your favorite gadget. Since it doesn't get the signal to perform an action, it just won't do it.

Be that as it may, a more famous autoimmune disease is known as type 1 diabetes, a condition that occurs as a result of the destruction of insulin-producing cells in the pancreas. These cells, called beta cells, are microscopic factories that make insulin, a hormone that drives sugar from our blood and into the cells of our body that need it. That's why people with diabetes have high blood sugar. It's because insulin lowers blood sugar. Anyways, in type I diabetes, the insulin-producing cells are basically bombed by our immune system like airplanes bombed factories in World War II, rendering them useless and their products very scarce.

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