hg4_lect28免疫系統(tǒng)的遺傳學(xué)(已修改)
2025-10-07 22:39 本頁面
【正文】 Geics of the Immune system Immune system protects us against foreign material proteins, viruses, bacterial infections Immune system has two major divisions. NonSpecific Response block entry of foreign agents into the body block the spread of foreign agents if they get into the body Specific Responses antibodymediated immunity humoral response cellmediated immunity – cellular response Foreign versus Self To protect the body from harmful anisms, the immune system identifies foreign molecules as “nonself” and destroys those cells. Molecules recognized by the immune system are called antigens. Antigens are usually protein fragments or carbohydrates. During development, the immune system removes ponents that recognize “self”. Immune response to one’s own body is called autoimmunity. 1. Physical barriers skin, mucous membranes and their secretions infection fighting chemicals,in tears, saliva, other body fluids 2. Nonspecific Innate defenses phagocytosis (engulfing cells) inflammatory response fever antimicrobial proteins plement, collectins, cytokines 3. Specific response Acquired Immunity Humoral immune response B cells, antibodies, memory cells Cellular immune response T cells, cytokines, memory cells Bacteria Viruses Acquired response Mucous membranes Physical barriers Cilia Innate response Cytokines Antimicrobial secretions Macrophages Macrophages present antigens Cellular response T cells Cytokines Cytotoxic T cells Humoral response B cells Memory B cells Plasma cells Antibodies Inflammatory response A nonspecific response triggered by injury peration of bacteria skin, respiratory, digestive, urinary or reproductive tract Two main players histamine plement Histamine dilates local blood vessels increases capillary permeability Result is redness, heat and swelling heat unfavorable to microanisms mobilizes white blood cells (monocytes) raises metabolic rate of surrounding cells Complement chemotaxsis agent recruits in WBC to injury site The Inflammatory Response starts with release of histamine and other chemicals ends with WBC cleaning up the debris Complement System chemical defense system that kills microanisms named the plement system because of the way it works together with the immune system are a series of proteins, C1, C2 , etc C5C9 form a large multiprotein plex MAC membraneattack plex MAC inserts itself into the membrane of invading microanisms creates a pore disrupts control of ion balance cells burst Antimicrobial chemicals on the nonspecific response collectins recognize the sugar moieties present on the surface of foreign cells cytokines interferons (chemical scouts), alert other cells to the presence of invaders also antiviral interleukins (fever) high temp kills some infecting bacteria lowers blood iron levels tumor necrosis factor Specific, Adaptive Immunity Acquired Response Invoked when the inflammatory response and plement systems fails Requires stimulation. Response tim
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