Section3Vascular PhysiologyVenacavaAorta(3.0 cm)(2.5 cm)HeartRegulationofbloodfiowVeinsArteries(3.0 cm)(0.5 cm)ArteriolesEndothelial(30 μm)Capillaries/cell(6μm)Smoothmuscle
Section 3 Vascular Physiology
Outline: Functional parts of blood vessels·Hemodynamics·Arterial blood pressure.Microcirculation. Venous pressure and venous return. The Lymphatic System
• Functional parts of blood vessels • Hemodynamics • Arterial blood pressure • Microcirculation • Venous pressure and venous return • The Lymphatic System Outline
Functional parts of blood vesselsVessel CharacteristicsConnective TissueSmoothMuscleElasticvessels(WindkesselVessels)EndothelitmMuscularandElastic,ThickwalledArteryDistributionvesselsMuscular,LittleconnectiveResistancevessels(Precapillarytissueresistance vessels)ArterioleEndothelialExchangevesselslayer,nomuscleShunt vesselsCapillaryDistributionvesselsThin walls withsomesmoothResistancevessels(postcapillarymuscleVenuleresistancevessels)Thin walled withsmoothmuscleCapacitancevesselsflacidVein
Elastic vessels (Windkessel Vessels) Distribution vessels Resistance vessels (Precapillary resistance vessels) Shunt vessels Exchange vessels Capacitance vessels Functional parts of blood vessels Distribution vessels Resistance vessels (postcapillary resistance vessels)
FunctionsofEndothelialCells1. Serve as a physical lining that blood cells do not normally adhere to inheartandbloodvessels2. Serve as a permeability barrier for the exchange of nutrientsmetabolicandproducts,andfluidbetweenplasmaand interstitialfluid; regulate transport of macromolecules and other substances.3. Secrete paracrine agents that act on adjacent vascularsmoothmuscle cells; including vasodilators-prostacyclin and nitric oxide(endothelium-derivedrelaxingfactor,EDRF)-andvasoconstrictors-notablyendothelin-1.4.Mediateangiogenesis (newcapillarygrowth)
Functions of Endothelial Cells 1. Serve as a physical lining that blood cells do not normally adhere to in heart and blood vessels. 2. Serve as a permeability barrier for the exchange of nutrients, metabolic and products, and fluid between plasma and interstitial fluid; regulate transport of macromolecules and other substances. 3. Secrete paracrine agents that act on adjacent vascular smooth muscle cells; including vasodilators- prostacyclin and nitric oxide (endothelium- derived relaxing factor, EDRF)- and vasoconstrictorsnotably endothelin-1. 4. Mediate angiogenesis (new capillary growth)
5. Play a central role in vascular remodeling by detecting signals andreleasing paracrine agents that act on adjacent cells in the bloodvesselwall.6.Contribute to the formation and maintenance of extracellularmatrix7. Produce growth factors in response to damage8. Secret substances that regulate platelet clumping, clotting, andanticlotting.9. Synthesize active hormones from inactive precursors (chapter 14)10.Extract or degrade hormones and other mediators (chapters 11,13).11. Secrete cytokines during immune responses (chapter 18)12. Influence vascular smooth muscle proliferation inthe diseaseatherosclerosis
7. Produce growth factors in response to damage. 8. Secret substances that regulate platelet clumping, clotting, and anticlotting. 9. Synthesize active hormones from inactive precursors (chapter 14) . 10.Extract or degrade hormones and other mediators (chapters 11, 13). 11. Secrete cytokines during immune responses (chapter 18). 12. Influence vascular smooth muscle proliferation in the disease atherosclerosis. 6. Contribute to the formation and maintenance of extracellular matrix. 5. Play a central role in vascular remodeling by detecting signals and releasing paracrine agents that act on adjacent cells in the blood vessel wall
I.HemodynamicsBlood flowQ=△P/R= (P1-P2)/RQ2PAPFlow=FAlA2r=radiusCopyight2002,Elsevir Science (USA),Allinighsresed
Blood flow Q= ΔP/R = (P1-P2)/R I. Hemodynamics
Q: cardiac output, 5 L/minQ= PA/RR: total peripheral resistancePA: aortic pressureRIGHTLEFTHEARTWNGTotal PeripheralVascularBRAINResistance (TPVR)Parallelsystem:1/TPVR=1/R,+1/R..Ponal验ThusRisalwayslessthananyindividual resistanceLIVERSPLEENSerial systemRou=R,+R.KIDNEYMUSCLESThusRuis alwayslargerthanCross sectional area(A)anyindividualresistanceofall open capillaries(Eg.8-1):SKINA=(10/(10)=0.1mFATBONE
Q: cardiac output, 5 L/min R: total peripheral resistance PA: aortic pressure Q= PA /R
ResistanceofbloodflowPoiseuille Law: Q=TT△Pr4/8nLd=11ml/min:. R= 8 nL / Tr4d=2P =16ml/min100mmHgd=4Q= △P/ R256ml/minAn: viscosityr: radius of the vesselOSmallvesselL: length of the vesselBLargevesselr (radius) : main determinant of blood flow
Resistance of blood flow Poiseuille Law: Q=πΔPr4 /8ηL η: viscosity r: radius of the vessel L: length of the vessel ∴ R= 8 ηL / πr 4 Q= ΔP/ R r (radius) : main determinant of blood flow
Il.Arterial blood pressureBlood pressure (BP)is the pressure ofcirculating blood on the walls of blood vesselsDIAGNOSTECNAISSystolicpressure(maximumSYSDIAduring one heart beat) ;0/PDiastolic pressure(minimum in between two heartAsphygmomanometerbeats).adeviceusedformeasuringarterialpressure
II. Arterial blood pressure Blood pressure (BP) is the pressure of circulating blood on the walls of blood vessels. A sphygmomanometer a device used for measuring arterial pressure Systolic pressure (maximum during one heart beat) ； Diastolic pressure (minimum in between two heart beats)
1.QualificationsStiffarteriesElasticarteriesVolume of circulatingbloodHeart pumping (power)+1Peripheral ResistancezSystolic/pulsepressureySystolic/pulsepressureDiastolicflow习DiastolicflowElasticity of aorta+心and arteries
1. Qualifications ④ Elasticity of aorta and arteries ② Heart pumping (power) ③ Peripheral Resistance ① Volume of circulating blood