The Immune System

The Immune System

The immune system is a network of organs that contain cells which

recognize foreign substances and destroys them. All living organisms

are exposed to harmful substances and most can protect themselves in

several ways, either with physical barriers or chemicals that repel

and kill them. It protects vertebrates against viruses, bacteria,

fungi and other parasites. These viruses are called pathogens.

The immune system is known to help in the fight against cancer. A type

of white cell, which is called the killer cells, is able to identify

tumour cells simply by its change in its surface membrane. Other

cells, called the helper cells, assist the killers to multiply and

they then connect themselves to the cancerous cells to destroy them.

There are two types of defence - the innate and the adaptive. The

innate includes barriers like the skin and antibacterial enzymes

within tears. The adaptive is based on specialized white blood cells

which are lymphocytes and they respond to invasions by

micro-organisms. Antibodies are chemicals produced by B cells, they

circulate in the blood that attacks disease and causes organisms, T

cells attack organisms head on, and these cells can memorize earlier

infections and therefore can act fast to avoid further attacks. The

defence of the immune system helps to provide protection against

infectious disease as well as some malfunctions of the internal body.

If the infectious organism splits the skin or maybe one that is not

killed off by chemicals, for example the enzymes found in tears or the

saliva, the immune and inflammatory response come into action. Some of

the signs of fighti...

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... cells. They are found both inside and outside of the human body and

are on guard at all times. The immune system is regulated by the

nervous system and the endocrine system. These in turn are influenced

by the feedback from different parts of the body.

SUMMARY

The immune is a collection of cells that keeps a note of the pathogens

that invade and it is able to destroy them. This makes the body immune

to that disease. The immune system is responsible for warding of

infection through the infection fighting cells and chemicals.

References

1. Anatomy & physiology, T Patton

2. Compton's encyclopaedia CD-ROM

3. Pears cyclopaedia

4. Health psychology, S Taylor

5. The Human Body, Dr T Smith

6. Grey's anatomy

7. DK family encyclopaedia

8. Foods that harm foods that heal, Readers Digest