The Immune System

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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... ... middle of paper ... ... 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

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