immunoch1 - Immunology Ch1: Elements of the immune system...

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Immunology Ch1: Elements of the immune system and their roles in defense *in medicine, the greates triumph of immunology has been vaccination or immunization, a procedure whereby severe disease is prevented by prior exposure to the infectious agent in a form that cannot cause disease. I. Numerous commensal microorganisms inhabit healthy human bodies a. More than 200 microbial species live in the healthy adult human gut and contribute about two pounds of body weight. i. Commensal species – “they eat at the same table. b. The community of microbial (Any minute, simple, single-celled form of life, especially one that causes disease) species that inhabits a particular niche in the human body –skin, mouth, gut, or vagina is called a flora c. Animals have evolved along with their commensal species and have become not only tolerant but dependent of them. i. Commensal organisms enhance human nutrition by processing digested food and making several vitamins ii. They also prevent disease, presence helps prevent colonization by dangerous, disease causing microorganisms. II. Pathogens are infectious organisms that cause disease. a. Any organism with potential to cause disease is a pathogen b. Any organism that colonizes the human body to no ill effect for much of the time but causes illness if the body’s defenses are weakened or if a microbe goes to the ‘wrong’ place is called an opportunistic pathogen c. Pathogens can be divided: i. Bacteria ii. Viruses iii. Fungi: which are a group of related microorganisms iv. Parasites : a less precise term used to embrace a hetergenous collection of unicellular protozoa and multicellular vertebrates (mostly worms) III. The skin and mucosal surfaces form barriers against infection
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a. The skin is the first defense, forms a tough impenetrable layer of epithelium protected by layers if keratinized cells. i. Epithelium is general name for layers of cells that line the outer surface and inner cavities of the body ii. The skin can be breached by physical damage and expose tissues, rendering them vulnerable to infection b. The lining of the respiratory, gastrointestinal, urogenital tracts are most vulnerablw to microbial attack. i. Such surfaces are known as mucosal surfaces or mucosae and are continually bathed in the mucus they secrete ii. In the respiratory tract, mucus is continually removed through action of epithelial cells bearing beating cilia and is replenished by mucus secreting goblet cells so it is continually cleansed of unwanted materials, including infectious microorganisms that have been breathed in IV.The innate immune response causes inflammation at sites of infection a. Infections generally stay localized and are extinguished within a few days witout illness or incapacitation and this is done through the innate immune system or I IS. b.
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This note was uploaded on 05/18/2010 for the course BICD bicd 100 taught by Professor Soowal during the Spring '08 term at UCSD.

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immunoch1 - Immunology Ch1: Elements of the immune system...

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