opyright@ The McGraw-Hill Companies, Ine Permission required for reproduction or display TABLE 12-4 Functions of Endothelial Cells I. 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 adiacent vascular and nitric oxide(endothelium-derived relaxing factor smooth muscle cells; including vasodilators-prostacycli EDRF)and vasoconstrictors--notably endothelin-l 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) I 1. Secrete cytokines during immune responses( Chapter 18) 12. Influence vascular smooth-muscle proliferation in the disease atherosclerosis
Hemodynamics(血流动力学) Blood flow Q= AP/R=(P1-P2)/R Pressure gradient Resistance Blood flow
Hemodynamics（血流动力学） • Blood flow Q= DP/R = (P1 -P2 )/R
Q: cardiac output, 5 L/min Q= PA/R R: total peripheral resistance PA: aortic pressure RIGHT LEFT HEART Total Peripheral vascula Resistance(TPVR) Parallel system 1/TPVR= 1/R,+1/R GUT Thus R is always less than LIVER any individual resistance LEEN Serial system RER.+R Cross sectional area Thus R. is always larger tha of all open capillanes any individual resistance Eq8-1) A=(10(103)=0.1m SKIN BONE FAT
Q= P A/R Q: cardiac output, 5 L/min R: total peripheral resistance PA: aortic pressure
Resistance of blood flow Poiseuille law:Q=π△Pr4/8nl m: viscosity r: radius of the vessel L: length of the vessel R=8nL/ir Q=△P/R Jean Louis Marie Poiseuille lpwa-zai(April 22, 1799-December 26, 1869) was a French physician and physiologist. Poiseuille was born in Paris, france From 1815 to 1816 he studied at the Ecole Polytechnique in Paris. He was trained in physics and mathematics. In 1828 he earned his D Sc degree with a dissertation entitled Recherches sur la force du coeur aortigue. he was interested in the flow of human blood in narrow tubes
Poiseuille Law: Q=pDPr4 /8hL h: viscosity r: radius of the vessel L: length of the vessel Q= DP/R Resistance of blood flow R= 8hL/pr 4 Jean Louis Marie Poiseuille \pwä-'zəi\ (April 22, 1799 - December 26, 1869) was a French physician and physiologist. Poiseuille was born in Paris, France. From 1815 to 1816 he studied at the École Polytechnique in Paris. He was trained in physics and mathematics. In 1828 he earned his D.Sc. degree with a dissertation entitled Recherches sur la force du coeur aortique. He was interested in the flow of human blood in narrow tubes
r: main determinant of blood flow A d 1 1 ml min 100mm 16 ml min d=4 256 ml min B Small vessel Large vessel
r: main determinant of blood flow