MIBO Study Guide Test 3 - Chapter15:InnateImmuneResponses

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Chapter 15: Innate Immune Responses First line of defense: Anatomical barriers Skin and mucous membranes Physical separation Membranes bathed in antimicrobials secretions Skin Difficult to penetrate 2 main layers Dermis : tightly woven fibrous CT Epidermis : many layers of epithelial cells, outermost layer is  keratinized Mucous Membranes Constantly bathed with mucus Some sites sweep away trapped material  Mucociliary escalator  of respiratory tract Antimicrobial Substances on Skin and Mucous Membranes Lysosyme  Enzyme that degrades peptidoglycan Found in tears, saliva, blood, and phagocytes Peroxidase Converts H 2 O 2  to reactive O 2 Found in saliva, body tissues, and phagocytes Lactoferrin Sequesters iron from microorganisms Found in saliva, some phagocytes, blood, and tissue fluids Defensins Antimicrobial peptides inserted into microbial membrane Found on mucous membranes and in phagocytes Normal Flora Microorganisms found growing on body surfaces of healthy individuals Not technically part of the immune system Protects through  competitive exclusion
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Covers binding sites Competes for nutrients Second line of defense: Cells of the immune system Always found in normal blood Numbers change during infection Blood cell formation:  hematopoiesis Blood cells (including immune cells) originate from  hematopoietic stem  cells  in bone marrow Stem cells triggered to differentiate by  colony-stimulating factor General Categories of Blood Cells Red blood cells/ erythrocyte s: carry oxygen in the blood Platelets : important in blood clotting Fragments of magekaryocytes White blood cells/ leukocytes : host defenses Four categories of leukocytes: 1.  Granulocytes Neutrophils/polymorphonuclear leukocytes : most abundant in innate  response Basophils : Involved in allergic reaction Eosinophils : Important in expelling parasitic worms, active in allergic  reactions 2.  Mononuclear Phagocytes Monocytes:  immature form that circulates in blood Macrophages : mature form Present in most tissues Abundant in spleen, liver, lymph nodes, lungs, and peritoneal  cavity Phagocytes: specialized cells that engulf and destroy microbes and cellular  debris Act as sentries, are alerted to signs of invasion More phagocytes can be recruited from blood stream as needed 3. Dendritic Cells Branched cells involved in adaptive immunity
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Function as scout in tissues Engulf material in tissue and bring it to cells of adaptive immunity 4. Lymphocytes Involved in adaptive immunity 2 major groups: B lymphocytes/B cells T lymphocytes/T cells Also:  natural killer cells Cell Communication In order for immune system to respond, cells must communicate with each other Cell surface receptors  are the eyes and ears of the cell
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This note was uploaded on 06/21/2011 for the course MIBO 2500 taught by Professor Walker during the Spring '08 term at University of Georgia Athens.

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MIBO Study Guide Test 3 - Chapter15:InnateImmuneResponses

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