Immune System Quiz

1. How does the immune system provide an immediate non-specific immune response?

     There are multiple ways in which the immune system can provide an immediate non-specific immune response. One way is through an inflammatory response. This occurs after tissue is damaged by bacteria, extreme pH levels, or heat. This damage causes histamine, bradykinin, and prostaglandin are released. These causes swelling because these hormones cause an overflow in the blood vessels into the damaged tissue cells.

   The other way is to use chemical barriers, which can be fatty acids, secreted antimicrobial peptides, or enzymes such as phospholipase and lysozyme. These barriers counteract the antigens in order to protect the body from getting an infection. The different reactions each of these barriers have vary greatly, for example some of react therapeutically while others attack certain polymers on the outside of invading bacteria.


      A third way is to use a complement system, which uses complement antibodies from the immune system to destroy invading bacteria. This system is made up of 25 proteins, and after the activation of a single protein, the rest become activated. This causes a release of molecules designed to target the bacteria's cell wall and cause it to implode.

2. How does the immune system activate T and B cells in response to an infection?
   
     B and T cells are types of lymphocytes found in the immune system. They are the primary defense of our immune system. T cells are broken down into "killer" T cells (Cytotoxic) and "helper" T cells and B cells are antigen receptors. The killer T cells have CD4 that is a growth stimulant so that more of these killer T cells are created. These killer T cells can target and kill toxic cells. They are activated when the T cell receptor binds with an antigen.

3. How does the immune system respond to a later exposure to the same infectious agent?

     One way is the use of memory cells (ex. T or B cells). They are called memory cells because they have devices that are specifically for recognizing specific pathogens. For example if you get the chicken pox once, you can not get it again because these memory cells will remember it and attack it extremely effectively.
     Another way is using Major Histocompatibility Complex (MHC). This is a group of molecules on the surface that bind together to prevent the pathogen from entering the system. This is split up into 3 classes.

4. How does the immune system distinguish self from non-self?

     One method is the ability to distinguish between "self markers" which exist on everybody's molecules and are unique for every individual. This allows the immune system to easily tell which molecules our part of our bodies and which are invaders.
     Another method is antigens, which are substances that set off an immune response. They do this by binding with immune receptors. This can trick the immune system very easily, because it believes that it is binding with a self cell.

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