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TheFunctionofBlood1.Agianttransportationsystem,O2,CO2,nutrients,wastes,hormone,etc2.homeostaticfuntion.Organismtriestokeepbloodcompositionstableandithelptoholdinterstitialenvironmentstability3.Buffersystem,tomaintainthepH,temperatureetc4.Defense,Defenseagainstbloodlossorbleeding(hemostasis),bloodcoagulation;DefenseagainstforeignbiologicalmaterialorimmunologicaldefenseNote:Torealisethosefunctionsbloodhastobepermanentlycirculating3.1CompositionandPhysicalandchemicalPropertiesofBloodPlasma50~55%BloodBloodcell(corpuscles,formedelements)45~50%Serumfibrinogen3.1.1BloodCompositionHematocrit(HTC)比容[‘hemətəkrit]3.1.1.1Plasma•Water93%•Protein65~85g/L(AlbuminMW69000,Globulin170000,Fibrinogen40000)•Electrolyte(Na+,Cl－,HCO3－)•Othersubstances•Redbloodcell(RBC,erythrocyte)•Whitebloodcell(WBC,leukocyte)•Platelet(thrombocyte)3.1.1.2Bloodcell(formedelement)•Bloodvolumeisabout7~8%ofbodyweight,about5Linaaverageadulthuman•BloodvolumeisdeterminedbyinjectingaknownamountofdyelikeEvanblueintothebloodstreamanddeterminingitsconcentrationafteritmixeswiththetotalcirculatingbloodandbeforeitdisappearfromthecirculation(about10min)AmountofinjecteddyePlasmaVolume=ConcentrationofdyeinbloodPlasmavolumex100Totalbloodvolume=%plasma3.1.2BloodVolume(血量）•Osmoticpressureofplasma(300mOsmforhuman)crystalosmoticpressure(298.7mOsm)colloidosmoticpressure(1.3mOsm)•PlasmapH7.35~7.45forhuman•Specificgravityofblood1.050~1.060Specificgravityofplasma1,025~1.030•Viscosityofbloodabout5timesgreaterthanthatofwater,ismarkedlyinfluencedbytheconcentrationoferythrocyteandplasmaproteins.3.1.3PhysicalandchemicalPropertiesofBloodNormalSaline3.2BloodcellPhysiology3.2.1血细胞生成的部位和一般过程•血细胞生成的部位(造血器官)胚胎早期卵黄囊2-3个月胚胎肝、脾4个月以后肝、脾、骨髓婴儿骨髓(肝脾可补充)成年人骨髓(仅限于一些扁骨和长骨的骨骺部)•造血微环境是指造血干细胞定居的、存活、增殖、分化和成熟的场所(T淋巴细胞在胸腺中成熟)，包括造血器官中的基质细胞、基质细胞分泌的细胞外基质和各种造血调节因子。造血微环境在血细胞形成的全过程当中起调控、诱导和支持作用。•造血过程和造血干细胞造血(hemopoiesis[,hi:məupɔi’i:sis])过程就是各类造血细胞发育和成熟的过程•造血干细胞(hemopoieticstemcell)•定向祖细胞(committedprogenitors)集落(colony)•前体细胞(precursors)3.2.2RedBloodCellPhysiology3.2.2.1Erythrocytecountandappearance•Erythrocytecount4.0~5.5x1012formen,3.5~5.0x1012forwomen.•Erthrocytesarebiconcavediscswithadiameterofabout7~8microns.Thematurehuman(mammal)erythrocytehasnonucleus,butothervetebratesdoes.•ItcostenergyforErythrocytetokeeptheirnormalshape.•Itcontainshemoglobin(Hb),about1/3ofmass•MainfunctionistocarryoxygenMicroscopicViewsBirdBloodCatBloodDogBloodFishBloodFrogBloodSnakeBloodHumanBloodHorseBlood•Hbconcentrationis120-160g/Lformen,110-150g/Lforwomen..•TheHbmoleculecontains4subunits,everyonewithheme[hi:m](亚铁血红素）andglobinAnaemia[ə’ni:miə]贫血Anaemiaisaconditioninwhichthehemoglobinconcentrationinthebloodisbelowadefinedlevel,resultinginareducedoxygen-carryingcapacityofredbloodcells.3.2.2.2PhysiologicalPropertiesandFunctionofRedBloodCells•Permeabilityoftheerythrocytemembrane红细胞膜的通透性•Plasticdeformationoferythrocyte红细胞的可塑变形•Suspensionstability悬浮稳定性Erythrocytesedimentationrate(ESR)红细胞的沉降率Rouleauxformationoferythrocyte红细胞的叠连•Agglutinationoferythrocyte红细胞的凝集•Osmoticfragility渗透脆性和Hemolysis溶血•Functiontransportationofoxygenandcarbondioxide•Erythropoiesis红细胞生成红细胞生成的部位、所需原料铁、叶酸和VB12生成过程生成的调节BPA(爆式促进激活物)EPO雄激素红细胞的破坏averagelifespan120days，90%被巨噬所吞噬，10%在血管中破损。•Anemia贫血急性失血、缺铁性(小细胞）贫血、巨幼红细胞贫血、镰刀状红细胞贫血(sicklecellanemia)•polycythemias红细胞增多症（脱水、骨髓造血过多）