The immune system is
our body's defense system against infections and diseases. Organs, tissues,
cells, and cell products work together to respond to dangerous organisms (like
viruses or bacteria) and substances that may enter the body from the environment.
There are three types of response systems in the immune system: the anatomic
response, the inflammatory response, and the immune response.
- The anatomic response physically
prevents threatening substances from entering your body. Examples of the
anatomic system include the mucous membranes and the skin. If substances
do get by, the inflammatory response goes on attack.
- The inflammatory system works
by excreting the invaders from your body. Sneezing, runny noses, and fever
are examples of the inflammatory system at work. Sometimes, even though
you don't feel well while it's happening, your body is fighting illness.
- When the inflammatory response
fails, the immune response goes to work. This is the
central part of the immune system and is made up of white blood cells,
which fight infection by gobbling up antigens. About
a quarter of white blood cells, called the lymphocytes, migrate to the
lymph nodes and produce antibodies, which fight disease.