BloodPressure-LostandHoundBloodhoundsIncorporated…血压和猎犬猎犬纳入了…

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1、BloodPressureBloodPressureFig15-4HydrostaticPressurecreatedbyventricularcontractilitybecomesthedrivingforceforbloodflowPulsatilebloodflowinarteriesElasticarteriesexpandandrecoilforcontinuousbloodflow.Thisisthe“pulse”thatwecanfeel.Pulsewavedisappearspastarteriolesandtheprecapillarysphincte

2、rsArteriesvs.VeinsEndothelialliningthroughoutthecardiovascularsystemandheartLessstickythanteflonArterieshavemoresmoothmusclethanveinsArteriescanvasoconstrictVeinsare“stretchy”orcompliantVeinshavevalvestopreventbackflowofbloodArteriesdon’thavebackflowduetopressuregradientCardiovascularSyste

3、mBloodFlowAortatomajorarteriestominorarteriesenteringorganstoarteriolestocapillariestovenulestoveinsleavingorganstovenacavaCardiovascularsystemtransportsmaterialsthroughoutthebodyNutrients,water,gasesMaterialsthatmovefromcelltocellWastesthatthecellseliminateWhyDoesBloodFlow?Liquidsandgases

4、flowdownpressuregradients(ΔP)AregionofhigherpressuretoaregionoflowerpressureBloodcanflowinthecardiovascularsystemonlyifoneregiondevelopshigherpressurethanotherregionsPressureGradientsPressureiscreatedinthechambersoftheheartwhentheycontractBloodflowsoutoftheheartThehigherregionofpressureAsb

5、loodmovesthroughthesystempressureislostduetofrictionbetweenthefluidandthevesselwallsPressurefallsthefartherthebloodmovesfromtheheartHigherpressureintheaortaLowestpressureinthevenaecavaejustbeforetheyemptyintotherightatriumBloodPressure(BP)MeasurementsVentricularpressuredifficulttomeasurem

6、easurearterialBPBPhighestinthearteries–fallscontinuouslythroughoutsystemiccirculation(Why?)Readas“Systolicoverdiastolic”–normalvalue120/80mmHg2003:Newrangeforbloodpressurereadingsbetween120/80and139/89“Prehypertension”Diastolicpressureinventricle:?mmHgBloodFlowRateP/RPressureofFluidinMo

7、tionDecreasesoverDistancePressureinafluidistheforceexertedbythefluidonitscontainerThecontaineristhewallofthearteryforbloodpressureHydrostaticPressureThepressureexertedifthefluidisnotmovingForceisexertedequallyinalldirectionsonthecontainerCapillariesCapillaries