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ID:41634368
大小:6.55 MB
页数:98页
时间:2019-08-29
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1、•Whydoorganismscontractdiseases?•Whathappenswhenanorganismcontractsadisease?•Whatfactorscanhelp(orhinder)thelikelihoodthatwewillcontractadisease?•Whathappenswhenanorganismisinjured?•Whatfactorscanhelp(orhinder)thelikelihoodthatwewillrecoverfromaninjury?Unit4:TheBody’sD
2、efenses•Reading:Chapter24•LectureOutline:1.Innateimmunityandadaptiveimmunity2.TheLymphaticsandtheImmuneSystem3.HumoralandCell-MediatedImmuneResponses4.ImmuneDisordesTheFirstLineofDefense:Skin•Thedead,outerlayerofskin,knownastheepidermis,formsashieldagainstinvadersandse
3、creteschemicalsthatkillpotentialinvaders•Youshedbetween40-50thousandskincellseveryday!TheFirstLineofDefense:MucusandCilia•Asyoubreathein,foreignparticlesandbacteriabumpintomucusthroughoutyourrespiratorysystemandbecomestuck•Hair-likestructurescalledciliasweepthismucusin
4、tothethroatforcoughingorswallowingDon’tswallowedbacteriahaveagoodchanceofinfectingyou?TheFirstLineofDefense:SalivaWhat’sthefirstthingyoudowhenyoucutyourfinger?•Salivacontainsmanychemicalsthatbreakdownbacteria•Thousandsofdifferenttypesofbacteriacansurvivethesechemicals,
5、howeverThinkofthehumanbodyasahollowplastictube…Thefoodisdigestedwithintheholeinthetube,butitneveractuallyentersintothesolidplasticmaterial.TubeinnersurfaceTubeoutersurfacePlasticinterior~DigestiveSystem~~Skin~~Body~TheFirstLineofDefense:StomachAcid•Swallowedbacteriaare
6、brokendownbyincrediblystrongacidsinthestomachthatbreakdownyourfood•Thestomachmustproduceacoatingofspecialmucusorthisacidwouldeatthroughthestomach!Escherichiacoliiscommonandplentifulinallofourdigestivetracts.Whyareweallnotsick?•Thesebacteriaaretechnicallyoutsidethebodya
7、ndaidindigestingmaterialwecannot•OnlyifE.ColiareintroducedinanunnaturalmannercantheybreakthroughthefirstlineofdefenseandharmusTheSecondLineofDefense:WhiteBloodCells•Ifinvadersactuallygetwithinthebody,thenyourwhitebloodcells(WBCs)begintheirattack•WBCsnormallycirculateth
8、roughouttheblood,butwillenterthebody’stissuesifinvadersaredetectedWhiteBloodCells:Phagocytes•Thesewhitebloodcellsarer
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