Blood Flow VelocityRegional Blood FlowCerebrovascular CirculationLaser-Doppler FlowmetryPulsatile FlowBlood PressureVascular ResistanceFlow CytometryHemodynamicsRheologyUltrasonography, DopplerXenon RadioisotopesMicrospheresDogsMicrocirculationUltrasonography, Doppler, ColorUltrasonography, Doppler, TranscranialTime FactorsOxygenVasodilationHeart RateOxygen ConsumptionRenal CirculationPulmonary CirculationCerebral ArteriesHyperemiaLiver CirculationCarbon DioxideModels, CardiovascularArteriesMiddle Cerebral ArterySplanchnic CirculationEchocardiography, DopplerTomography, Emission-ComputedBrainBlood VolumeUltrasonography, Doppler, PulsedVasodilator AgentsOxygen RadioisotopesXenonBlood Circulation TimeNeural ConductionPlethysmographyCollateral CirculationOphthalmic ArteryGene FlowCoronary CirculationMuscle, SkeletalReference ValuesDiastoleLegCapillariesVasoconstrictionRetinal ArteryHindlimbReproducibility of ResultsRetinal VesselsFemoral ArteryNitric OxideIschemiaPartial PressureUmbilical ArteriesBiomechanical PhenomenaHeartCatsStress, MechanicalBlood Gas AnalysisSystoleUltrasonographyRats, Sprague-DawleySkin TemperaturePerfusionCarotid ArteriesAnalysis of VarianceAdenosineChoroidVasomotor SystemDoppler EffectSkinArteriolesModels, BiologicalBlood ViscositySwinePregnancyMagnetic Resonance ImagingSheepEchocardiography, Doppler, ColorPlacental CirculationUltrasonography, PrenatalPhysical ExertionHomeostasisBrain IschemiaMuscle ContractionAntipyrineAcetazolamidePulsePressureTomography, Emission-Computed, Single-PhotonRabbitsEndothelium, Vascular