Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson today on immune system disorders and diseases. Today we're going to be talking about various immune system disorders and diseases and how they affect the body. So we're going to start today by talking about allergies.
So allergies are substances that enter the body and cause an immune system attack. And so this immune system is responding to an allergen in the case of allergies. And an allergen is generally a harmless substance that enters the body and causes this immune system attack, such as dust or pollen or food or sometimes medications, pet dander, et cetera. So they're these normally harmless substances that are causing a person to have an immune system attack. And that's what allergies are.
So basically it causes a person's mucous membranes to become inflamed. So we're going to take a look here at what happens when a person is experiencing allergies. So let's say that you are allergic to pollen, as many people are. So you are outside on a day, just kind of hanging out in the yard. And you inhale some pollen as you're outside.
So as you inhale that pollen, it'll enter your system. And it's going to attach or bind to B-cells in your body. So this is a B-cell. And this is going to be pollen. So it attaches to receptors on this B-cell.
What then happens is that it causes effector B-cells to make and secrete IgE antibodies to that allergen. It's making IgE antibodies to that allergen. So these are the antibodies being produced to this allergen by these effector B-cells. So desensitization therapy basically what that does is it's a way in order to treat allergies that basically stimulates the body to produce IgG antibodies instead of IgE. So it's a treatment for allergies.
But anyway, so these IgE antibodies are produced by these effector B-cells. And then what's going to happen is that those antibodies are going to attach to mast cells. So this would be a mast cell. And a mast cell is a type of white blood cell that's found in your tissues.
So when those antibodies attach to this mast cell, it stimulates the release of histamines. So these in here, these little dots are histamine granules. So when these antibodies attach to the mast cell, it causes these histamines granules to be released into the body.
And the release of these histamine granules is what causes inflammation. So it causes the inflammation of your mucus membranes, which leads to that yucky feeling when you have allergies. So antihistamines are drugs that you can buy-- you can go to the drugstore and buy them over the counter-- that provide short-term allergy relief, because it blocks the effects of these histamines here. So in a nutshell, that's kind of how allergies work.
So anaphylactic shock is a type of whole-body allergic reaction. It's a very, very serious entire body allergic reaction. And generally, somebody who goes into anaphylactic shock would then have to be injected with epinephrine, which is a drug that will help reverse the effects of that allergy.
So let's talk about some autoimmune disorders next. So autoimmune disorders are when the immune system attacks normal healthy body cells. So these different disorders right here are examples of autoimmune disorders. So again, autoimmunity is a type of disorder in which the person's own body cells are attacked.
So rheumatoid arthritis is one of these types of disorders where joint tissue is attacked. And basically, this causes the joints to become inflamed. And it can be really painful. So rheumatoid arthritis is a type of autoimmune disorder.
Type I diabetes is another type of autoimmune disorder in which insulin-producing cells of the pancreas become attacked. So those cells become attacked. The pancreas can no longer produce insulin, which can be an issue. So people who have Type I diabetes generally have to use injectable insulin in order to control their blood glucose levels.
And lupus is another type of autoimmune disorder that's characterized by a butterfly rash on the face. And basically, with lupus, antibodies are produced to a person's own DNA. So lupus has a wide range of effects on the body. It's not just one particular effect. It can affect many organs of the body, because of the way in which a person's own DNA is attacked.
And lastly, we're going to talk about deficient immune responses, or immunodeficiency. So this is when a person's own immune system is weak or can even be almost nonexistent. It's not functioning normally or properly.
So AIDS is a common example of immunodeficiency. And it stands for Acquired Immune Deficiency Syndrome. So AIDS is a disease caused by the HIV virus. And basically what happens is that a person's own immune system is just not working, so it makes them susceptible to contracting many other types of diseases.
And generally, because their immune system is so weak, they can't fight these other diseases off. So their immune system is very weak or almost nonexistent. So usually a person who has AIDS will generally die of some sort of other disease, because they're so susceptible to these other diseases because of their weakened immune system.
So this lesson has been an overview on immune system disorders and diseases.
Source: Video and Images Created by Amanda Soderlind
Welcome to this lesson on HIV and AIDS. Today, we will be talking about what HIV and AIDS is, how it's transmitted, and how it can be treated. So first of all HIV, which stands for Human Immunodeficiency Virus. Human immunodeficiency virus is a virus that causes the disease AIDS, and AIDS stands for Acquired Immune Deficiency Syndrome. So HIV is a virus that causes this specific disease.
In HIV, basically what it does is it attacks the immune system and kills lymphocytes, such as helper T cells, and also attacks macrophages and dendritic cells, which are another part of your body's immune system. So what this does, is it leaves your body vulnerable to infection and rare forms of cancer. So it's basically a virus that attacks and destroys your immune system so that your body can't fight off any other types of diseases or illnesses or cancers that you might come across.
HIV is also a retrovirus. And what this means, is that rather than its genetic information being in the form of DNA, it is in the form of RNA. So the HIV virus's genetic information is in the form of RNA. So what happens is that the virus will insert its genes into a person's DNA and replicate in that way, and we'll talk about that process a little bit more in just a moment here.
So what's going to happen then is that once a person becomes infected with the HIV virus, the immune system will first react normally. But this virus will replicate so quickly that eventually the body is not able to keep up with it. And the HIV virus actually produces billions of new viruses each day within your body's helper T cells.
So at first, the person will experience various minor infections as a result of the number of helper T cells dropping. But eventually, once that number of helper T cells gets too low, it leaves your body susceptible to more serious diseases. And those more serious diseases are oftentimes will end up killing a person who has HIV or AIDS.
So let's take a look at how HIV is affecting the cells within your body to cause this disease. So HIV is a virus that has these proteins all over its coat. OK, so these are all proteins.
Within the virus, within the inside, you have your viral RNA and you have a viral enzyme. And this viral enzyme it's called reverse transcriptase. So viral RNA, along with that enzyme, will produce viral DNA. And that viral DNA will then mix with the DNA of the host cell, and then will be transcribed to produce new viruses.
OK, so what happens, like I said, we're going to pretend that this-- this here is going to be a lymphocyte. So that virus is going to enter into the lymphocyte. Here's the nucleus, and here's the DNA of that lymphocyte. So the DNA of the virus will mix with the DNA of the host cell, OK?
Then what's going to happen is that DNA is going to be transcribed. And once that DNA is transcribed, it's going to produce new virus particles. So then, these new virus particles are going to be produced. So these new virus particles will be assembled from viral RNA and proteins. So basically, the virus is infecting healthy cells using the cells DNA in order to produce more viruses.
So transmission of HIV is through bodily fluids, especially blood and semen, but other bodily fluids can also transmit this virus as well. So it can enter the body through any sort of cut or abrasion, and oftentimes it's spread by sharing needles or it's sexually transmitted. It can also be passed from mother to child through child birth or through breastfeeding.
So Africa right now is the country that has the highest population of infected people worldwide. So for the treatment of HIV, there is actually no cure for HIV and AIDS, but there is a treatment that can slow the process down. And it includes a cocktail of drugs.
So the reason that there's no treatment for HIV and AIDS, is because it mutates rapidly and develops resistance to drugs very easily. And also the reason for it, is that since it injects its own DNA into the host cell's DNA, you can't really remove the HIV genes from someone else's DNA. It's very difficult. So that's what makes it uncurable right now.
So the treatment involves a cocktail. We call it a cocktail of drugs. So basically, this cocktail involves a protease inhibitor which blocks the action of HIV protease. And HIV protease is an enzyme that's required to make new viruses.
So we have a protease inhibitor. And also, this cocktail involves two anti-HIV drugs. So this cocktail of drugs, as I mentioned, doesn't cure HIV and AIDS, but it helps slow it down and gives the person a better chance for living longer. So this lesson has been an overview on HIV and AIDS.