医学教学课件：Circulatory system

Chapter9

Circulatory

system

---Closedtubularsystem---BloodcirculatoryorcardiovascularS---LymphvascularSThecardiovascularSheartarteryveincapillary1.

Capillaries1)LM:endothelium:basementmembrane:pericyte:/flattenedwithprocesses/function:i.

supportii.undifferentiatedcellendothelialcell:processes–microvilli-like,finger-likedvesicle/60-70nm,constituteabout25-35%oftotalvolume/transendothelialchannel

function:transportlargemoleculesandstorageofmembrane(forenlarge,enlongated,pore-formedandmicrovilli)EM:classification①Continuouscapillary:

---Structuralfeature:endothelialcell:-morevesicles-tightjunctionbasallamina:complete---Distribution:CT,MT,lungandCNS②Fenestratedcapillary---Structuralfeature:endothelialcell:-havefenestraeorpore(60-80nminD,with4-6nmdiaphragm)basallamina:complete---Distribution:gastrointestinaltract,endocrineglandandrenalglomerulus③Sinusoidcapillaries

(enlargecapillary)---Structuralfeature:endothelium:gap,porebasallamina:incompleteorno(absent)---Distribution:liver,spleenandbonemarrow2.

Artery---largeA:aorta,pulmonarytrunk---medium-sizedA:allnamedA,thediameter>1mm(radialA,ulnarA)---smallA:300um<D<1mmMedium-sizedA

–muscularA---Tunicaintimaendotheliumsubendotheliallayer:CT-collagenousF-elasticF-smoothmuscleinternalelasticmembrane:wave-liked,pink-coloredband-elastin---Tunicamedia:thickestlayersmoothmuscle:10-40layersof,circularlyelasticF:producedbySMcollagenousF:producedbySM---Tunicaadventitia:

LCT–withsmallBV-vasavasorum,NFandLVexternalelasticM2)LargeA:elasticA---Structuralfeatures:a.

Tunicaintimaisthick,andinternalelasticMisnotprominantb.

Tunicamedia:consistsof40-70layersofelasticmembrane,CFandSMLargeAelasticMSM3)SmallA:---largeSA:internalEM3-4layersSMnoexternalM---smallSA:nointernalM1-2layersSM2.

Veins---threetype---correspondwithAexceptforLV---threelayers---structuralfeatures:a.largerdiameter,thinnerwalls-collapsedb.

nointernalandexternalelasticmembrane,sotheboundariesbetweenthreetunicaarenotveryclearc.containsmoreCT,lesssmoothM,SMarearrangedinbundlesd.

veinvalve:/infoldingoftunicaintima/semilunar-liked/preventbackflowofblood4.

Heart---atrium(rightandleft)---ventricle(rightandleft)ThewallofheartESEsubendocardiallayerendocardiummyocardiumepicardium1)Thewallofheart---endocardium:

endothelium

subendotheliallayer:moredenseCT-containfibroblast,CF,EF,SM

subendocardiallayer:LCT,withBV,NandconductingS-Purkinjefiber---myocardium:cardiacM:a.

atrialmuscle:/atrialgranules:0.3-0.4uminD,containatrialnatriureticpolypeptideorcardionatrinb.

ventricularM:thick,long,branchesLCT:richincapillaries*atrioventricularfibrousannulus:DCT---epicardium:viscerallayerofpericardium-serousmembrane:mesotheliumLCT:morefatcell-subepicardiallayer---cardiacvalve:formedbyinfoldingofendocardium:endothelium+DCTpreventthebackflowofblood2)ConductingS①components:---sino-atriolnode(SAnode):locatedinepicardiumofrightatrium---atrio-ventricularnode(AVnode)andbundles(AVbundles):locatedinsubendocardiallayer---networkofPurkinjefiber:②threetypesofcellsa.pacemakercell(Pcell):mainlydistributedinSAandAVnodesmall,fusiformorpolygonalinshapedenclosedbyDCTlessorganelle:myofibril,plasmalemmalvesiclesandmoreglycogenb.transitionalcell:mainlydistributedinperipheryofSANorAVNandAVbundleThestructureisbetweenpacemakercellandcardiacMthinnerandshorterthanCMmoremyofibriltha