Being Immune

Introduction: Welcome to the next section of Unit II - Topic One. This section is going to deal with some definitions of terms involved with immunity, recognizing foreign invaders, how the body defends itself, and a quick look at antibodies.

Definitions:

*Definitions are from Mader textbook, chapter seven.

Immunity: "Ability to combat diseases and cancer, includes lines of defense" (pg 128).

Bacteria: Single-celled prokaryotes without a nucleus.

Virus: Not composed of cells and are obligate parasites. Viruses don't live without a host.

Antigens: Foreign molecules to the immune system.

B cells and T cells: lymphocytes that are capable of recognizing antigens.

Lymphocytes: Specialized white blood cells that function in specific defense (Pg G-11).

Helper T-Cells: T-cell that secretes cytokines that stimulate all kinds of immune system cells (Pg G-9)

There are many more vocabulary involved in immunity system actions, but these are a few commons one that will be used during the rest of this section.

Invasion!

There are two main classes of foreign invaders. There is bacteria first. Here is a picture from http://www.researchmagazine.uga.edu entitled "Bacteria Gone Bad."

I found this to be an appropriate picture because most bacteria are not disease causing; bacteria can go bad. Here is a more traditional view of bacteria from http://www.ou.edu.

The other class are viruses. According to Frolich, slide 19 of 'Blood, Oxygen, and Immunity,' "Viruses are escaped parts of genome or DNA." Viruses rely on a host to live. Here is a common depiction of a virus from http://www.ucmp.berkeley.edu.
Here is a picture of the influenza virus I found at http://www.rkm.com.auI really like this picture of the flu virus. It looks like a very colorful other part of some system that actually would of some assistance, but in actuality, it makes one feel pretty awful.

Viruses and bacteria are are considered to be "invaders." What happens in the body is very neat. During development, the body is exposed to its own cells and the proteins. The immune cells that begin to attack our own cells are eliminated and the remainders are what become the T- and B-Cells. This process is known as "clonal selection." Once developed, the T- and B-Cells recognize invaders and kill them, but won't kill the bodies own cells.

Defend the Body!

There are two types of defenses: Nonspecific and Specific. Nonspecific is further broken down into two lines of defense which are: barriers to entry and inflammatory response.

Barriers to entry has a first line of defense which is the bodies built-in barriers, such as skin and mucous membranes. It also has some chemical barriers, such as secretions of oil glands, perspiration, saliva, tears, and acid pH of the stomach.

Inflammatory response is like the second line of defense. It is characterized by four symptoms: redness, heat, swelling, and pain. The body then sends out all of its signals to get white blood cells, platelets (if needed), and any other things needed.

The whole idea of inflammatory response reminds of a hospital emergency situation. For example, an alarm goes off. Everyone has their specific duties. At least two doctors closest to the emergency are to respond. Nurses come with crash carts and defibrilators. Then come nursing aides or patient care technicians as more support staff. It seems like the inflammatory response does the same thing. It sends out the alarm to the brain saying there is something going on here, usually characterized by pain. Excess blood flow occurs, which is like getting everyone to the scene. Then the white blood cells come, which is like the doctors who determine what action needs to be taken.

Antibody

On page 132 of the Mader textbook there is table 7.2 at the bottom of the page. It explains the class, presence, and function of certain antibodies.

An antibody is protein produced in response to the presence of an antigen; each antibody combines with a specific antigen (Pg G-2). Here is a picture of antibodies attaching to a virus to prevent it from reproducing or being transported further throughout the body. This picture was found at http://images.healthcarecentersonline.com.Antibodies float freely in the blood stream but are considered T- and B-Cell receptors when attached to one or the other. Susumu Tonegawa was recognized with the Nobel Prize for his discovery of antibody diversity. Here is a picture of an antibody from http://www.biology.arizona.edu that depicts the binding sites, variable, constant, and light and heavy chain.


Conclusion: There you have it! We just went over major information about what all helps one out to be immune. Next up, we are going to take a very brief look at HIV/AIDS. The next section is going to give a a few websites that give great information.