Chapter 43 - Immune System

Chapter 43 - Immune System - 43.1 Innate Immunity provides...

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43.1 Innate Immunity provides broad defenses against infection - - innate immunity = present before any exposure to pathogens & is effective from birth - largely non-specific - quickly recognizes & responds to broad range of microbes regardless of precise identity External Defenses - Intact skin is barrier that cannot normally be penetrated by viruses / bacteria - even tiny abrasions may allow passage - mucous membranes lining digestive, respiratory, & genitourinary tracts restricts entry - certain cells also produce mucus fluid that traps microbes & other particles - microbial colonization is inhibited by washing action of mucous secretions, saliva & tears that constantly bathe surfaces of exposed epithelia - secretions provide hostile environment for microbes - secretions from oil glands & seat glands give skin pH 3 – 5 - acidic prevent colonization - hepatitis A: can survive gastric acidity & enter body through digestive tract - secretions contain antimicrobial proteins - lysozyme = enzyme that digests cell walls of many bacteria - present in tears, saliva, & mucous secretions - can destroy bacteria as they enter upper respiratory tract / openings around eyes Internal Cellular & Chemical Defenses - Depend mainly on phagocytosis = ingestion of invading microorganisms by certain white blood cells (phagocytes) - Produce certain antimicrobial proteins - Help initiate inflammation limit spread of microbes Phagocytic Cells - 1. Phagocytes attach to prey via surface receptors bind to structures found on microorganisms but not normal body cells -
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This note was uploaded on 04/17/2009 for the course BISC 220 taught by Professor Mcclure during the Spring '09 term at USC.

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Chapter 43 - Immune System - 43.1 Innate Immunity provides...

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