血管血液心脏课件

Section 3 Physiology of the Blood Vessels . Functional Anatomy of Blood vessels （各类血管的结构功能特点） n1.Windkessel vessel(弹性贮器血管) n2.Distribution vessel(分配血管) n3.Resistance vessel(阻力血管) n4.Exchange vessel（交换血管） n5.Capacitance vessel （容量血管） n6. Shunt vessel (短路血管) 1.Windkessel vessel (弹性贮器血管) aorta rich of elastic fibers; elasticity 指主动脉、肺动脉主干及其发出的大的分支 。 function: to store energy to keep continuity of diastolic now; to buffer variation of BP。 1. Windkessel Vessel - Aorta and big arteries. 2. They transiently store blood during systole, and then shrink to produce onward blood flow during diastole. they convert the sharp pressure fluctuations in the left ventricle (0 to 120 mmHg) into much smaller pressure fluctuations in the arteries (80 to 120 mmHg). And convert the intermittent ventricular ejection into continuous blood blood in the vessels This function of large arteries is known as Windkessel effect. 2. distribution vessel 2. Distribution Vessel Middle arteries These arteries are rich in smooth, which will systole or diastole under some physical and chemical factors. Together with resistance vessels, they match the blood flow to different organs with their requirements. Distribution of Cardiac Output 3.Resistance vessel (阻力血管) small artery rich of smooth muscles sympathetic innervations; function: formation of BP; to produce the role in blood distribution venules. The amount of blood flowing through a particular capillary bed is determined in part by the action of the precapillary sphincter of muscle. These muscles allow only 5% - 10% of the capillary in bed skeletal muscles, for example, to be open at rest. 4. Precapillary Sphincter muscle- 4.Exchange vessel(交换血管 Capillary; pores slow flow; large section; function: formation of interstitial fluid. Exchange Vessel Capillary uthe walls of capillaries are composed of only one cell layer a simple squamous epithelium, or endothelium. uThe absence of smooth muscle and connective tissue layers permits a more rapid transport of materials between the blood and the tissues. 5.Capacitance vessel （容量血管） venous system; large volume and extensibility; sympathetic nerve; function: to store blood 2) R: frictional force produced when blood fIows through blood vessels. Q = P / R P1P2 A Q = P1 P2 R 血流速度(V ) = Q/A V主V毛 A 2.血流速度 (velocty) 血液中的一个质点在血管内移动的线速度。 与血流量成正比，与横截面积成反比。 aorta velocity 20cm/s, Capillary velocity 0.03cm/s segment inversely The velocity of blood flow in each segment of the circulation is inversely proportional to its cross-sectional area. Laminar flow and turbulent flow Laminar flow blood flows in streamlines with each layer of blood remaining the same distance from the wall; Laminar flow Turbulent flow blood flow in all directions in the vessel and continually mixes within the vessel. C, constriction; A, anterograde; R, retrograde because of the velocity of blood flow is too great, is passing by an obstruction, making a sharp turn, passing over a rough surface) Re=VD/ Re2000 Turbulent flow 3.Resistance(血流阻力,R) It is frictional force produced when blood fIows through blood vessels. Q= （P1- P2)r4 / 8 L Q= (P1- P2) /R 8 L R= r 4 R= 8 L/ ( r 4) R1/r4 Note that the resistance (R) of a vessel is directly proportional to the blood viscosity () and length (l) of the vessel, but inversely proportional to the fourth power of the radius ( r ). the diameter of a blood vessel plays by far the greatest role of all factors in determining the resistance ( R ) of blood flow. 4.Blood Pressure (血压, BP) It is a force exerted by the blood against unit area of the vascular wall. Blood Pressure is stored energy (potential energy) Q = P / R P = Q . R Major Theme: Blood Pressure is stored energy (potential energy) Physical Definition: Force per unit area Pressure = dyne/cm2; 1mmHg=0.133kPa or 133Pa . Arterial Blood Pressure and arterial pulse （）Arterial Blood Pressure Stroke Volum Heart Rate Resistance Elastic of Large Vessels Relationship Between Blood Volume and Vascular Volume 1.Formation Of Arterial Pressure Conditions： There is a enough blood in the cardiovascular system. The ventricles contract There is a resistance in the blood vessels. Elasticity of Windkessel vessel 1）Enough blood filled in the system （循环系统内足够的血液充盈。） mean circulatory filling pressure MCFP （循环系统内血液充盈的程度可用循环系统平均充盈压表示 ） when heart beat is stoped, the pressure in any point of cardiovascular system is equal. This pressure is called MCFP. 动物实验中，使心脏停跳，此时循环系统各处压力相等，约7mmHg 即 循环系统平均充盈压。 systemic circulation, 7 mmHg; pulmonary circulation, 10 mmHg. MCFP反映血量和血管容积之间的关系 血量 or 循环系统容积 MCFP （2）Ventricular ejection (Cardiac pumping) prerequisite 动能 Cardiac Work BP（ systolic ） 势能 动能 贮存 BP （ diastolic ） （3）Peripheral resistance 是形成动脉血压的充分条件。 小动脉和微动脉的阻力作用 1/3收缩期流向外周 搏出量 2/3暂存主动脉、大动脉 BP Blood Pressure: Generated by Ventricular Contraction （4）Elasticity of Windkessel vessel diastolic blood pressure continuous blood flow in diastole buffering blood pressure 大动脉弹性贮器作用 Pressure and resistance in the various portion of the systemic circulations. The decrease in pressure in each part of the systemic circulation is directly proportional to the vascular resistance. 2. Normal Range of Arterial Pressure Systolic pressure (Ps) the maximum of the pressure during systole Diastole pressure (Pd) the minimum pressure during diastole Pulse pressure the difference between Ps and Pd Mean arterial pressure the average pressure throughout each cardiac cycle. Mean arterial pressure (Pm) = Pd + Pulse pressure / 3 Mean arterial pressureMean arterial pressure More Blood Pressures: Pulse and Mean Arterial Pressures Normal range of arterial pressure At rest, the arterial pressure of Chinese adult young people should be: Ps, 100 120 mmHg, Pd, 60 80 mmHg, Pulse pressure 30 40 mmHg, Mean arterial pressure 100mmHg hypertension Adult at rest, Ps=140mmHg Pd =90mmHg Elevated BP forces the heart to work harder even though stroke volume is not increased! Hypertension will eventually lead to myocardial hypertrophy and, finally, heart failure. hypotension Ps=90mmHg or Pd =60mmHg Measurement of the arterial pressure Direct (inserting a cannula into the artery) and indirect (auscultatory) method Stethoscope Blood Pressure (BP):Blood Pressure (BP): 4. Factors Influencing arterial pressure (1) Stroke Volume: other factor fixedness: Stroke volume Systolic aortic blood Volume Systolic pressure aorta blood velocity diastole end aorta remain Diastolic pressure Pulse pressure (2) Heart Rate: other factor fixedness: Heart rate ( 180/min) Diastolic phase becomes short blood flow to the periphery Diastole end aorta remain Diastole pressure Pulse pressure (3) Peripheral Resistance : other factor fixedness: Peripheral Resistance diastole end aorta remain Diastolic pressure Pulse pressure (4) Windkessel effect buffer Systolic pressure not too high maintain diastolic pressure not too low arteriosclerosis Systolic pressure diastolic pressure Pulse pressure arteriolosclerosis Peripheral Resistance diastolic pressure Pulse pressure 5）proportion between blood volume and vascular capacity (血量和血管容积比例) Grave lose blood blood volume MCFP Stroke volume BP vascular capacity （大量毛细血管扩张） BP Factors Determining Arterial Pressure (1) Stroke volume - Ps (2) Heart rate - Pd (3) Total peripheral resistance (Pd) (4) Action of Windkessel vessel (aorta and other large arteries) Pulse pressure (5) Mean circulatory filling pressure . Venous Pressure and Return (静脉压和静脉回流) ()Venous Pressure 1.Peripheral venous pressure (外周静脉压 ) It is the pressure in venule. 体循环微静脉血压约为1520mmHg, 右心房作为体循环的终点，血压最低，接近于“0”。 Peripheral venous pressure venous pressure in the organs Properties: 1) Low pressure 2) Affected by the hydrostatic pressure 3) Usually veins are collapsed. Transmural pressure = Blood pressure - The pressure adjacent tissues exerted on the blood vessel. If the transmural pressure is negative (smaller than 0), the vein is collapsed 平卧位： 大部分血管基本相同； 直立位： 足部约90mmHg 心脏平面以上 -矢状窦-10mmHg 2.Central venous pressure (CVP 中心静脉压) def: It is the pressure in right atrium or large vein in thorax. (412cmH20) determinant: venous return blood volume ability of cardiac pump（心脏射血能力） Peripheral venous pressure Clinic meaning cardiac pump function CVP Venous return blood volume CVP Venous return velocity () Venous Return 1.Concept: The quality of blood flowing from veins into the right atrium per minute. Driving force: pressure gradient 2.Factors affecting venous return (1) mean circulatory filling pressure 反映血管系统充盈的指标 血管充盈程度愈高 Venous Return (2) cardiac contractility 心脏收缩舒张是静脉回流的原动力，心肌收缩时将 血液射入动脉，舒张时则从静脉抽吸血液. Cardiac contractility stroke volume ventricular pressure in diastole period blood from atria and large veins to ventricle venous return (3) posture (or gravity) 体位变化对静脉血压的影响： for sleeping in lie To standing position lower limbs transmural ressure Venous expand Venous Return CVP Stroke volume regulation Sympathetic Parasympathetic Going from lying Venous diastolic end Stroke To standing position return volume volume Cardiac Blood output pressure Baroreceptors sensory neurons Medulla oblongata Sympathetic Parasympathetic Vasoconstriction of arterioles Stroke volume Heart rate Total peripheral resistance Cardiac ouput Blood Pressure Negative feedback response (4)Action of “muscular pump” (or venous pump) (5) respiration movement. Negative pressure in the thoracic cavity that changes with respiratory movement dilation of venae cave increase of venous return V.Formation and Factors effecting of Interstitial Fluid The Interstitial Fluid Water within the body accounts for 60% of the total body weight (body fluid) 2/3 intracellular compartment 1/3 extracellular compartment (80%, interstitial fluid; 20%, blood plasma) The distribution of extracellular fluid between the plasma and interstitial compartments is in a state of dynamic equilibrium. Tissue fluid is not normally a “stagnant pond” but is rather a continuously circulating medium, formed from and returning to the vascular system. In this way, the tissue cells receive a continuously fresh supply of glucose and other plasma solutes that are filtered through tiny endothelial channels in the capillary walls Formation and Factors effecting of Interstitial Fluid 1. Formation and Circumfluence Effective filtration pressure +capillary blood pressure +30mmHg +colloid osmotic pressure of interstitial fluid +15mmHg -plasma colloid osmotic pressure -25mmHg -interstitial hydrostatic pressure -10mmHg colloid osmotic pressure 10mmHg hydrostatic pressure = C R T（菲茀尔定律） ：以大气压为单位的渗透压 C ：某溶液克分子浓度 R：气体常数=0.082 T：绝对温度=2730C Formation of Interstitial Fluid Pc : pressure in the capillary Pif : hydrostatic pressure of interstitial fluid P : colloid osmotic pressure of the blood plasma if : colloid osmotic pressure of the interstitial fluid Effective filtration pressure = （毛细血管血压+组织液胶体渗透压) （血浆胶体渗透压+组织液静水压） 促进滤过力量 阻止滤过力量 capillary A = ( 30mmHg + 15mmHg ) ( 25mmHg + 10mmHg ) = 10mmHg capillary V= (12mmHg + 15mmHg) (25mmHg + 10mmHg) = - 8mmHg 2. Factors Determining Formation of the Interstitial Fluid Mechanism of Edema: Edema is an abnormally large collection of fluid in the interstitial space. From the physiology of capillaries and lymphatics, it can be deduced that edema may be due to one or more of the following causes: Factors effecting formation of interstitial fluid (1) capillary pressure (2) plasma colloid osmotic pressure (3) permeability of capillary wall (4) lymphatic return (1) Capillary pressure (2) Right heart failure systemic edema (3) Left heart failure pulmonary edema (4) Late pregnancy edema in legs and foot (pressure of uterus on inferior vena cava) (2) Plasma colloid osmotic pressure Protein malnutrition, liver disease (inadequate albumin synthesis ) or renal disease (protein loss in urine) hypoproteinemia low plasma colloid osmotic pressure (3) Permeability of capillary wall Inflammation or allergy leakage of abnormally large quantities of proteins from capillaries (4) Lymphatic drainage Lymphatics are the second circulatory system. Structurally, lymphatics are a network of blind-ended thin endothelial tubes. Although the endothelial lining is not fenestrated, the intercellular junctions are permeable to large molecules. Lymphatics collect proteins, lipids and other large molecules which leak out of capillaries into the interstitial space, to prevent the osmotic pressure of interstitial space from rising, and thereby prevent abnormal accumulation of fluid in the interstitial space. Reduced lymphatic drainage, e.g. in filariasis, or involvement of lymph nodes in malignancy local or systemic edema. 3.The function of lymph removing protein from interstitial fluid. (2) regulating balance between plasma and interstitial fluid ( reabsorption l0% of filtration fluid). (3)absorption nutrients (80%90% of fat )from gastrointestinal tract. (4) removing the particles such as RBC, bacteria, lymphatic cell, tissue cell in the interstiti