circulatory system循环系统

1Circulatorysystem2Bloodcirculatesthroughoutthebodyinthecardiovascularsystem,whichconsistsoftheheartandthebloodvesselsThissystemformsacontinuouscircuitthatdeliversoxygenandnutrientstoallcellsandcarriesawaywasteproducts.Alsofunctioningincirculationisthelymphaticsystem,whichdrainsfluidandproteinsfromthetissuesandreturnsthemtothebloodstream.3TheheartTheheartislocatedbetweenthelungs.Thethickmusclelayeroftheheartwallisthemyocardium.Thisislinedontheinsidewithathinendocardiumandiscoveredontheoutsidewithathinepicardium.Theheartiscontainedwithinafibroussac,thepericardium.Eachoftheupperreceivingchambersoftheheartisanatrium(plural,atria).Eachofthelowerpumpingchambersisaventricle(plural,ventricles).Thechambersoftheheartaredividedbywalls,eachofwhichiscalledaseptum.4Cardi/o:heartcardiocytecardiologycardiomalaciacardiomelanosisbradycardiatachycardiacoron/o:coronarycoronaryartery:thebloodvesselsthatsupplybloodtotheheartmuscle5Coronaryheartdisease(CHD)isaconditioninwhichpropercirculationofbloodandoxygenarenotprovidedtotheheartandsurroundingtissue.Thisresultisduetoanarrowingofthesmallbloodvessels,whichnormallysupplytheheartwithbloodandoxygen.Thetypicalcauseofcoronaryheartdiseaseisaconditionknownasatherosclerosis,whichtakesplacewithplaqueandfattybuilduponthearterywalls,narrowingthevessels.Somemorefrequentsymptomsofcoronaryheartdiseaseinclude:Angina(chestpain)HeartattackShortnessofbreath6coronavirus:Coronavirusesprimarilyinfecttheupperrespiratoryandgastrointestinaltractofmammalsandbirds.Fourtofivedifferentcurrentlyknownstrainsofcoronavirusesinfecthumans.Themostpublicizedhumancoronavirus,SARS-CoVwhichcausesSARS,hasauniquepathogenesisbecauseitcausesbothupperandlowerrespiratorytractinfectionsandcanalsocausegastroenteritis.Coronavirusesarebelievedtocauseasignificantpercentageofallcommoncoldsinhumanadults.7TheVascularSystemThevascularsystemconsistsof:1.Arteriesthatcarrybloodawayfromtheheart.Arteriolesaresmallarteriesthatleadintothecapillaries.2.Capillaries,thesmallestvessels,throughwhichexchangestakeplacebetweenthebloodandthetissues.3.VeinsthatcarrybloodbacktotheheartThesmallveinsthatreceivebloodfromthecapillariesanddrainintotheveinsarevenules.8Arteriesbranchanddivergeastheymoveawayfromtheheart。Theyformsmallerandsmallerdivisionscalledarteriolesandeventuallyterminateincapillaries.Venulesaresmallerveinsthatgatherbloodfromcapillary.Veinsmergeandconvergeintosuccessivelylargerbloodvesselsastheymovetowardstheheart.Capillariesnetworksarethesiteofgas,nutrientandwasteexchangebetweenthebloodandtherespiringtissues.9Wecandividecardiovascularsystemintwomaincirculations:thepulmonarycirculation(fromhearttolungstoheartagain)andthegeneralcirculation(fromhearttoallbodytissuestoheartagain);thefirsthasthetasktooxygenatevenousblood,thatreturnstotheheart,whereasthesecondleadsthisoxygenatebloodthrougharteriestoallbodytissues,inordertospreadoxygentoeverypartofthebody.10angi/o:bloodvesselangiotensinconvertingenzymeinhibitor:AngiotensinⅠisconvertedtoangiotensinⅡbyangiotensin-convertingenzyme.AngiotensinⅡcanbindwithangiotensinreceptor(AT,existinginvascularsmoothmuscle),leadingtovasoconstrictionandriseofbloodpressure.angiotensin-convertingenzymeinhibitorsuchasCaptoprilcanbindwiththeconvertingenzymes,thusangiotensinⅠcouldn'tbindtotheconvertingenzymesandwon’tbeconvertedtoangiotensinⅡ.11Vas/o:bloodvesselVasodilation:wideningofbloodvesselsresultingfromrelaxationofsmoothmusclecellswithinthevesselwalls,particularlyinthelargearteries,smallerarteriolesandlargeveins.Vasodilator:medicinesthatcanrelaxbloodvessels.Vasoconstriction:narrowingofbloodvessels12arteri/o:arteryarteriostenosisven/o,phleb/o:veinintravenousinjectionphlebitiscapillar-,capillo-:pertainingtocapillarycapillarectasiacapillaryangioma13hem/o,hemat/o,em=bloodhemorrhage:bleedinghematocytopenia:decreaseofbloodcellsanemia:areductioninthenumberofcirculatingerythrocytesorinthequantityofhemoglobin14LymphaticsystemThelymphaticsystemconsistsoflymphductswhichtransportlymphfluidsandlymphorganswhichcanproducelymphocytesandantibodies.Lymphorgansincludelymphnodes,tonsils,spleenandthymus.15Thelymphaticsystemisawidelydistributedsystemwithmultiplefunctions.Itsroleincirculationistoreturnexcessfluidandproteinsfromthetissuestothebloodstream.Thefluidcarriedinthelymphaticsystemiscalledlymph.AnotherfunctionofthelymphaticsystemistoabsorbdigestedfatsfromthesmallintestineThesefatsarethenaddedtothebloodneartheheart.Oneothermajorfunctionofthelymphaticsystemistoprotectthebodyfromimpuritiesandinvadingmicroorganisms.161.Componentofimmunesystemcenterimmuneorgans:bonemarrow,thymusImmuneorgansperipheralimmuneorgans:spleen,lymphnodes,skinmucousmembraneImmunocytes:Tlymphocyte,Blymphocyte,macrophage,naturalkilleretcimmunemolecules:antibody,cytokines(tumornecrosisfactor,interferoninterleukinetc),complementImmunesystem172.Antigen2.1Definition:Anantigenisanysubstancethatcausesyourimmunesystemtoproduceantibodiesagainstit.Anantigenmaybeaforeignsubstancefromtheenvironmentsuchaschemicals,bacteria,viruses,orpollen.Anantigenmayalsobefo