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