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Elongated

cellssimple

EndothelialcellsstorefactorVIIIinWeibelPaladebodies

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Heart:

EndotheliumsubendothelialCT(thinelasticand

collaenfiberswithSMCconnectstomocardium(Purkinjefibers);valvesofheart

Myocardium(tunicamedia):

cardiacmyocytesw/branching,intercalateddisks,striations,centralnuclei

Epicardium(tunicaadventitia):

thinlayerofCT(viscerallayerofserous

percarum,rouspercarum,nerves,anbloodvessels

Nointercalateddisc

BetweenEndocardiumandmyocardiumLieinsubendocardiumSpecializedcardiacmusclewithincrease

glycogenandmitochondriaanddecrease

Purkinjefibersspecializedcardiacmuscleswith increasedlcoenandmitochondriaand

decreasedmyofibrilsLargercellsandpalestaining

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CardiacMuscle

ElasticArteryCloseupontheTunicaIntimaandMedia

ELASTIC(Conducting)e.g..Aorta&itsmajorbranches,pulmonarytrunk

TunicaIntima

Endotheliumnonthrombogenic

SubendothelialCTSMC,collagenI&II,elastic,GroundSubstance+macrophages

IELpresentbutnotdistinct,mergeswithelasticfibersofT.media

Tunicamedia(mostdevelopedlayer)

40-70layersofimbricatedelasticfibers,aidindistensionandrecoil

InterspersedamongelasticfibersarecircularlyarrangedSMC,collagenfibersandGroundSubstance

Largeamountofelasticfibersinthetunicamedia

SMCsynthesizesextracellularfibersandgroundsubstance.

TunicaAdventitia

DenseIrregularCT,

wrnnrrrhvvrnnrvvrhv ,,,.

Guardsagainstoverexpansionofthevesselsbeyondphysiologiclimits.

Vesselsmaintainuniformandcontinuousmovementofbloodalongthevasculature.Insystole,elasticarteriesexpand,while

indiastolethevesselsrecoil.

Laminaeofelasticsheetshavefenestratedcapillariestosupplysmoothmusclethatrunbetweentosupplybloodvesselsand

nutrients

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ElasticArteryElasticStain,allthreetalers

ELASTIC(Conducting)i.eAorta&itsmajorbranches,pulmonarytrunk

TunicaIntima

Endotheliumnonthrombogenic

SubendothelialCTSMC,collagenI&II,elastic,GroundSubstance+macrophages

IELpresentbutnotdistinct,mergeswithelasticfibersofT.media

Tunicamedia(mostdevelopedlayer)

40-70layersofimbricatedelasticfibers,aidindistensionandrecoil

InterspersedamongelasticfibersarecircularlyarrangedSMC,collagenfibersandGroundSubstance

Largeamountofelasticfibersinthetunicamedia

SMCsynthesizesextracellularfibersandgroundsubstance.

TunicaAdventitia

DenseIrregularCT,

wrnnrrrhvvrnnrvvrhv ,,,.

Guardsagainstoverexpansionofthevesselsbeyondphysiologiclimits.

Vesselsmaintainuniformandcontinuousmovementofbloodalongthevasculature.Insystole,elasticarteriesexpand,while

indiastolethevesselsrecoil.

Laminaeofelasticsheetshavefenestratedcapillariestosupplysmoothmusclethatrunbetweentosupplybloodvesselsand

nutrients

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.

OnceyouseevasovasoruminTA(circled

nue

NV=nervivascularissympathetics

Tunica

Intima

Tunica

Media

unca

Adventitia

Characteristics:

AutosomaldominantCTdisorderwithCVDandocular

manifestations(lensmoveslessb/cfibersnotbeingheldin)

Fibrillinene1defectfibrillinlcoroteinthatmakesascaffoldonwhichelastinisdepositedelastic

fibers)

fibersoft.mediaweakenedwallaorticaneurysmanddissectiondeath.

AorticDissection:Hematomatearintunicaintimabloodleaksintotunicamediacausesdeath

properlyformedbulgeout

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MUSCULARARTERY(Distributing)eg.Femoral,Coronaryulnar,radial,brachialetcecreaseeasticmateriaanincreaseMin.meia.

TIntimaendotheliumSubendothelialCT(maybescanty)DistinctIELadistinctcharacteristicfeature.Undulating(lollipop)appearance,scallopedappearance

T.Media

640layersofSMCrespondtoneuralstimulationandcontrolBPFewelasticfibers&collagen

T.AdventitiaDistinctEEL .Vasovasorumbloodvesselsofbloodvessels

MUSCULARARTERY

MUSCULARARTERY

MUSCULARARTERY

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MUSCULARARTERYEM

Endothelialcell

closetotheIELcharacteristic

appearanceofarteries

SMALLARTERY

NicescallopedappearanceknowitisarteriesdifferentiatefromvenuleorductuleTunicaadventitiagetslessinsmallermusculararteriesTunicaMedia38layersofsmoothmuscles

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Smallestarteries

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Thinnerwalls

SparsesubendothelialCT

T.adventitiaismoredevelopedthantheT.media

Illdefinedtunicswiderlumenmore

collapsiblecomparedtocorresponding

arteries.

Tunicaintimalfoldsconnectedby

suepeumsysem

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T.Intima

EndotheliumsubendothelialCT.

(unidirectionalflow)

T.Media

rcuaryarrange+coagen+eastcers

T.Adventitia

MostdevelopedlayerCollagenI+elasticfibersLongitudinallyarrangedSMCcontracttopushbloodback

.

VenaCava

enaava

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CAPILLARIES eareroeseenocaparessconnuous layerofsmoothmuscleintunicmediaprecapillary

sphincter

,.toformaprecapillarysphincter.

Regulatesbloodflowtoareasofneedexample-duringexercise.

constrictionregulatesflowtoparticularorgan)Luminaldiameter79microns(ofRBC)

Differentlevelsofmetabolicexchange

Singlelayerofendothelialcells+basallamina

injurytoformbloodvessels&CT.Leucocytessqueezethroughtheintercellularjunctioninto

.

Remark:notetherestrictedpermeabilitiesintheorgansbarriers...Blood-brain,retina,thymic,testis,etcbarriers

Pin

Endothelialcells

Continuous/somatic-Capillary(TypeI)Completecontroloverdiffusionandtranscytoticprocessespinocytoticand

exocytoticvesicles,includingreceptormediated-endocytosisContinuousbasallamina

NofenestrationincytoplasmicmembraneEndothelialcellsarejoinedbytightjunctions.

Tightjunctioncontinuousringwhateverpassthroughlumen

gyterecarryromnseFlattenedsquamoustypecells

Pinocyticvesicles(caveolae)fortransportacrossthewall+-Sites:

MuscleTissue

Nervoustissue(CNS)LungsExocrineglandsTendonetc

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Endothelialcellsfarfromeachother

Rmicrovilliofhepatocytes

Discontinuous/sinusoidal-Capillary(TypeIII)eroratonsargeanvaraetatcanreacoseveramcra.DiscontinuousbasallaminasurroundedbyreticularfibresDiscontinuousendothelialcells

notightjunctionbasallaminalessornotpresentFenestrationspresentForevengreaterexchangeSites:liver,spleen,Bonemarrow

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Large

fenestration

Atherosclerosis:causedbyatheroma(fattyplaques)intunica

intima;decreasesbloodflowandweakenstheunderlyingtunicamediapronetoclotformation(thrombus)whichcantravelasanemboli;

obstruconischemiaofmocardiu m

Hypertension:causesdamagetosmallerbloodvesselsbyscarring,hardeningandnarrowingthem;makesthemlesselastic

Arterioles:radiusisequaltothethicknessofthewall;resistanceisinverselyproportionaltodiameter

PeripheralArteryDisease:causedbyatherosclerosis;pronetoheartdisease/stroke;painandnumbness,gangrene,buildupinareres

VaricoseVeins:resultfromweaknessintunicamediaThrombus:clottedmassofblood;embolus:transportedmassof