(b)++The+human+defence+systems+in+the+blood

 ** How the human body defense system works **
 * ** Lines of defense ** || ** What is the job of each line ** ||
 * First line of defense is surface protection. || This is composed from anatomical and physiological barriers that keep the microbes from penetrating sterile body compartments. These are not specific meaning that human�s skin is naturally immunity. ||
 * Second line of defense is cellular and chemical system. || It comes immediately into play when infection agents get past the surface protection. These are not specific. ||
 * Third line of defense is a specific host defense. || This is to be developed uniquely to each microbe and it is really powerfully. These are specific. ||

A good example for the three lines of body defense is a well-guarded island.

The first line of defense would be that there is lot of soldiers around the island. It is important to keep the first line powerful because they haven�t still got to the island and it is easier to keep the away. When they have got over the first line of defense there would be spare soldiers ready to attack immediately. Then when they have got through the second line of defense there would still be the third line where could be a specific assassin which is hard to get past.

  ** How your body can recognize foreign materials and invaders **

§ The name of the molecules that are recognized, and what they are. ** Antigens **  Antigens are anything that causes an immune response in an animal and they areon the surface of cells. Each cell in our body has an antigen that tells immune system that it is a part of us and should not be destroyed. Bacteria cells have different antigens that tell immune system that they are foreign and must be destroyed.

§ What part of your body recognizes them ** Antibodies ** Antibodies are proteins made by body’s immune system. They bind to specific antigens and remove them from the body.  media type="youtube" key="mIQBBgAcSdI" height="390" width="480"

§ How this system works

The immune system distinguishes foreign cells and cells from us in order to destroy foreign cells that can be very harmful to our body. When the body is invaded by foreign cells such as bacteria, viruses, or fungus, the immune system will recognize them as foreign and destroy them  § What happens when it goes wrong?  
 * ** Main Categories of Immune disorders ** || ** What happens ** ||
 * **Autoimmune Disorders** || It occurs when immune system attacks the body’s health cells instead of harmful antigens ||
 * **Immunodeficiency Disorders** || It occurs when a part of the immune system is not present or not working well. Some people are born with an immune deficiency and can get infected easily ||
 * **Allergic Disorders** || A lot of people suffer from allergies caused by an overreaction of the immune system. When antigens enter body, (dust, pollen, animal hair, bee stings, etc.) the immune system overreact and the antibodies release histamine, which results in allergic reaction ||

 <span style="font-family: 'Calibri','sans-serif'; font-size: 12pt; margin: 0cm 0cm 10pt;">** Phagocytosis and Immunity ** Phagocytosis

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Immune system · The immune system is our body defense system. · Organs, tissues, cells and cell products are working together so that they can respond to dangerous organism like viruses or bacteria and substances that may enter the body from the environment. · There is three types of response systems in the immune system: the anatomic response, the inflammatory response and the immune response · The anatomic response physically prevents the dangerous substances to enter your body. Example of this includes mucus and the skin. · The inflammatory response excretes the invaders from your body. Example of this is sneezing, runny nose and fever.

<span style="font-family: 'Calibri','sans-serif'; font-size: 12pt;">HINT: be careful to organize this section well. It should not just be a random series in info. You may well choose to incorporate your responses to questions (4) and (5) in your question three response