Chapter 12: Cardiovascular Physiology Vascular Physiology Vena cava Aorta 3.0cm 25cm) Heart Regulation of blood flow Veins Arteries (3.0 cmj (05cm Endothelial cell Capillaries (304m (6 um) Smooth muscle
Chapter 12: Cardiovascular Physiology Vascular Physiology
Lecture Outline Functional parts of blood vessels 。Hemodynamics Arterial blood pressure ·Microcirculation Venous pressure and venous return ·The Lymphatic System
Lecture Outline • Functional parts of blood vessels • Hemodynamics • Arterial blood pressure • Microcirculation • Venous pressure and venous return • The Lymphatic System
Functional parts of blood vessels Vessel Characteristics Connective Tissue Smooth Muscle Elastic vessels (Windkessel Vessels) Endothellum- Muscular and Elastic,Thick walled Artery Distribution vessels Muscular.Little connective Resistance vessels (Precapillary tissue Arteriole resistance vessels) Endothelial layer,no muscle ■ Exchange vessels Capillary ■ Shunt vessels Thin walls with some smooth muscle Venule Thin walled with smooth muscle ■ Capacitance vessels flacid Vein
Functional parts of blood vessels Elastic vessels (Windkessel Vessels) Resistance vessels (Precapillary resistance vessels) Exchange vessels Capacitance vessels Distribution vessels Shunt vessels
Copyright The McGraw-Hill Companies,Inc.Permission required for reproduction or display. TABLE 12-4 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 end 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 vasoconstrictors-notably endothelin-1. 4.Mediate angiogenesis(new capillary growth). 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. 6.Contribute to the formation and maintenance of extracellular matrix. 7.Produce growth factors in response to damage. 8.Secrete 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
Hemodynamics 。Blood flow Q=△P1R=(P-P2)/R Pressure gradient Resistance Blood flow
Hemodynamics • Blood flow Q= ∆P/R = (P1-P 2)/R
Q:cardiac output,5 L/min Q=PA/R R:total peripheral resistance PA:aortic pressure RIGHT LEFT HEART LUNG Total Peripheral Vascular BRAN Re sistance (TPVR) Parallel system: 1/TPVR=1/R,+1/R Thus R is always less than any individual resistance SPLEEN Serial system Ru=R,+R2… LUSCLES Cross sectional area(A) Thus R is always larger than of all open capillaries any individual resistance (Eq.8-1月 A=(10103=0.1m SKIN BONE FAT
Q= PA/R Q: cardiac output, 5 L/min R: total peripheral resistance PA: aortic pressure
Resistance of blood flow Poiseuille Law:Q=元△Pr4/8nL n:viscosity r:radius of the vessel L:length of the vessel R=8nLUπr4 Q=△PIR
Poiseuille Law: Q=π∆Pr4/8ηL η: viscosity r: radius of the vessel L: length of the vessel Q= ∆P/R Resistance of blood flow R= 8ηL/πr4
r:main determinant of blood flow A d=1 1 ml min d=2 16 ml min 100mm Hg d=4 256 ml min B ◎ Small vessel Large vessel
r: main determinant of blood flow
Arterial blood pressure Artery Vein -Tunica intma. Tunica media (nooth mu3c30】 Tunica externa 0oo5e他rcLs connective tissue) (epithetal ce到 Arteries Fox,Stuart I. Human Physiology 4th Brown Publishers
Arteries Arterial blood pressure
Blood pressure measurement 1.Direct(invasive)measurement technique 100 mm Hg pressure 0 pressure Moving sooted paper Float Anticoagulant solution Mercury Mercury manometer
Blood pressure measurement 1. Direct (invasive) measurement technique