Download The Immune System

Cory Collard
S#00448585
Biology 1090
Term Paper
7-7:50
The Immune System
Don’t you hate getting sick? Well you body does too. That’s where your body’s immune
system comes in. The immune system is a collection of cells and organs that protect your body
from disease and illnesses. It also gets rid of cells that your body produces that have become
damaged or are abnormal. This system also allows us to recover. It fights the harmful organisms
or pathogens if we do get infected. The organs in the immune system are the thymus, bone
marrow (including WBC), spleen, and the lymph nodes. The first line of defense is your body’s
skin, and mucus membranes. If anything gets past that, then there are white blood cells that will
attack it. There are also cells of the immune system called lymphocytes to help defend your body.
Your skin covers your whole body and acts as a shield against any harmful
microorganisms. But on your face you have openings to eat and breathe, and these are protected
by mucus membranes. Salvia in your mouth is slightly acidic and contains bacteria killing
enzymes and antibodies. There is also mucus in your nose that does these same things, and that’s
why sometimes you get a runny nose. Even though you might not like it, this is a good thing; it
means your body is working to protect you.
Sometimes you will get a break in your skin or a cut, and this will allow bacteria and
other harmful organisms to enter your body. You body needs to repair these openings quickly so
that nothing does get inside. To start the process of inflammation, your body releases the
chemical histamine that makes the blood vessels near the break widen. This allows more blood to
reach the area quickly to start to repair it. The inflammation also heats up the localized area, and
the heat will help to kill off bacteria.
Your body can also create inflammation throughout itself, where as inflammation is
localized to one area. When your body does this, you get what is called a fever. Chemicals called
pyrogens are released and this increases your body temperature. A fever raises your body
temperature from about 98.7 degrees or so, to about 100, but not more than 103 degrees. The
body does this because bacteria have a limited temperature range in which it can grow.
If the microorganisms make it past these lines of defense, then your body recognizes this,
and starts going into action to stop them from spreading. White blood cells (WBC) are
responsible for starting an immune response. The white blood cells are a collection of different
types of cells that are vital to making the immune system work. T-cells are one of these types,
and T-cells are divided into two different groups. T-helpers (T4 helpers) and T-killers or Tlymphocytes. The T-helper cells make the body’s immune system stronger by telling other white
blood cells (T-killer) of the presence of an antigen. T-killers go directly to killing certain tumor
cells, virus infected cells, and parasites. Both of the T cells are produced in the bone marrow, and
then they travel to the thymus to develop. B-cells or B-lymphocytes are another type of white
blood cell. B-lymphocytes meet the intruders and immediately start to clone themselves. The
main function for B-cells is to produce antibodies. Antibodies recognize and bind themselves to
viral substances and tell cells to surround and kill that cell. The antibodies are a Y-shape, and the
tips are sensitive to specific antigens. An interesting thing about B-cells is that they create
memory cells. These memory cells are now able to remember what the microorganism was, and
Cory Collard
S#00448585
Biology 1090
Term Paper
7-7:50
how to destroy it, and this allows the body to produce antibodies faster. The B-lymphocytes are
also produced in the bone marrow.
Another white blood cell is the Natural Killer cell. Natural Killer cells are like Tlymphocytes in that they also directly attack tumors such as melanomas and lymphomas. But
unlike the T cells, NK cells don’t need to be told by the T4 helper cells when to attack. Even
though they don’t need to be told by the helper cells, they can recognize the secretions of them,
and be more effective in killing the infected cells.
Macrophages help to regulate the immune systems responses. They travel around the
body and pick up antigens and bring them to T and B-cells. This then allows them T and B-cells
to begin attacking the infectious materials. Dendritic cells are like macrophages, but instead of
taking the antigens to the B and T-cells, they deliver them directly to the thymus, lymph nodes,
and spleen. They are also located in the bloodstream and bodily tissue.
Cory Collard
S#00448585
Biology 1090
Term Paper
7-7:50
Bibliography
Derkins, Susie. Insider’s Guide to the Body; The Immune System
Print. The Rosen Publishing Group, Inc. 2001
Boudreau, Gloria. The Immune System
Print. The Gale Group Inc. 2004