excessive responces to allergens due to hypersensitivity
Unit 1 - Write the Unit Title here
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2nd Line Of Defence
•Cytokines chemical messengers of the immune system. They are used by immune system cells to communicate with each other and with other body systems such as the nervous system. They are considered part of the 2nd line of defence because they are involved in the inflammatory response as well as the stimulation of other immune system cells.
1st line of defence
•The physical and chemical barriers that prevent the entry of pathogens into our body. •Intact skin acts as a physical barrier •Normal bacterial flora live in a symbiotic relationship with their host. They prevent the growth of parasitic bacteria on skin by competing with them for space and resources. These organisms existing in a symbiotic relationship with their host are known as commensals. •Mucous membranes within urogenital openings, trachea, bronchi, nasal cavity and mouth, trap microorganisms. Ciliated membranes have protrusions known as cilia-they sweep mucous away from the lungs. •Natural secretions
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3rd Line Of Defence
Antibodies are protein molecules which are produced in response to foreign antigens. The general antibody structure is a Y-shape and is made up of four polypeptide chains. Two long central heavy chains a joined together by disulphide bridges. The two light chains join to the heavy chain by hinge regions which are flexible and allow the antibody to bend if necessary to maintain a better link with the antigen. The variable region or the tips of the Y are the antigen binding sites. Most antigens are proteins or large polysaccharides. When antibodies bind to antigens they form cross links or agglutinate. The tail of the Y can bind to special receptors on phagocytes to enable them to engulf the antibody antigen complex.
Cells Of The Immune System
Describe here the main requirements for student homework.