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The body’s defenders. Contents. Pathogens and disease Major types of defense Nonspecific or innate immunity External defenses Internal defenses Specific or acquired immunity Lymphocyte activity. Types of acquired immunity Humoral (antibody-mediated) response Cell-mediated response - PowerPoint PPT Presentation
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The bodys defenders
ContentsPathogens and diseaseMajor types of defenseNonspecific or innate immunityExternal defensesInternal defensesSpecific or acquired immunityLymphocyte activityTypes of acquired immunityHumoral (antibody-mediated) responseCell-mediated responseImmunity to secondary infectionActive immunityPassive immunityBlood groups and transfusionsImmune disorders
Pathogens and diseaseBacteria
Two major types of defenses
Innate (nonspecific) immunity First line: External defensesExternal defenses
Innate immunity Second line: Internal defensesPhagocytes Attach to and ingest invading microorganismsInitiates the inflammatory responseMacrophages migrants or in lymph organsAntimicrobial proteinsComplement system lysis of invading cells, triggers inflammationInterferons activate macrophages, prevent cell-to-cell spread
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Inflammatory responseInnate immunity Second line: Internal defenses (cont.)http://www.sumanasinc.com/webcontent/anisamples/dynamicillustrations/inflammatory.htmlChemicals involved Histamines Prostaglandins Chemokines Pyrogens
Innate immunity Second line: Internal defenses (cont.)Natural killer (NK) cellsPatrol bodyAttack virus-infected body cells and cancer cellsApoptosis (cell death) in cells attackedCoelomocytes in invertebrates function in nonspecific immunity
Specific (acquired) immunityThird line of defenseLymphocytesFound in blood and lymphTypesB cells mature in marrowT cells mature in thymusHelperCytotoxicDisplay specificity to antigens (antibody generator)Have membrane-bound antigen-receptors
Two types of specific immune responses
B and T cells generate clones ofshort-lived activated effector cellslong-lived memory cells
Antibody action
Immunity memory cells initiate a faster, more efficient response upon reinfection
Active immunityOwn system develops antibodiesDevelops naturally in response to infectionDevelops following immunizationLong-lasting protection but may take a long time
Passive immunityAntibodies are passed from mother to fetus via the placentaAntibodies are passed from mother to infant via breast milk (colostrum)Antibodies may be injected into a nonimmune personImmediate, short-term protection
Blood groups and transfusionsProblems with transfusions and transplantsAntigens on RBCs will determine a persons blood type: A, B, AB, O bloodAnother RBC antigen: Rh factor Rh+ or Rh-
Immune disorders/diseasesAllergies hypersensitive responses to antigens called allergensAutoimmune diseases immune system loses tolerance for self and turns against certain molecules of the bodyImmunodeficient diseasesInborn or primaryAcquired or secondaryAIDS HIV attacks helper T cells