最新心泵PPT课件.ppt

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1、心泵心泵Section 1 The contractility of the heart Section 2 The pumping function of the heart u Cardiac cycle（心动周期）（心动周期）The cardiac events that occur from the beginning of one heartbeat to the beginning of the next are called cardiac cycle.Each cycle is initiated by spontaneous generation of an action p

2、otential in the sinus node.The conduction delay in the A-V node(1/10sec)allows the atria to contract ahead of the ventricles,thereby pumping blood into the ventricles before the strong ventricular contraction begins.Thus,the atria act as primer pumps(初级泵）初级泵）for the ventricles.The characteristics of

3、 a cardiac cycle Diastole is longer than systole Heart rate mainly affects diastole Time sequence of the events in a cardiac cycleAtrial systole Ventricular systoleIsovolumic contraction phaseRapid ejection phaseReduced ejection phase Ventricular diastoleIsovolumic relaxation phaseRapid filling phas

4、eReduced filling phaseFigure 10-3 Events of the cardiac cycle for LV function,showing changes in LA pressure,LV pressure,aortic pressure,ventricular volume,ECG,and the phonocardiogram.uFunction of atria as primer pumpsAtrial contraction usually causes an additional 25%filling of the ventricles;75%of

5、 the blood flows directly through atria into the ventricles.The heart usually can continue to operate even the atria stopping work unless a person exercises.u Heart sound（心音）（心音）The first heart sound:represents the beginning of ventricular contraction.The second heart sound:represents the beginning

6、of ventricular dilation.The third heart sound:heard at the end of ventricular rapid filling,caused by the vibration of ventricular wall and papillary muscle,found in some children,young people and HF.Gallop rhythm(奔马律奔马律):all the above 3 sounds appear.The forth heart sound(atrial sound):heard before

7、 the first heart sound,caused by atrial contraction and ventricular filling,usually can not be heard,found by phonocardiogram at the decrease of ventricular wall compliance.u Cardiac murmur（心脏杂音）（心脏杂音）Systolic murmurDiastolic murmuru Phonocardiogram（心音图）（心音图）Section 3 The evaluation of cardiac pumpi

8、ng functionu Stroke volume（每搏输出量）（每搏输出量）The blood output in each contraction of LV or RV,about 70ml at resting condition in an healthy adult.u Ejection fraction（射血分数，（射血分数，EF）u Minute volume(cardiac output)（每分输出量（每分输出量,心输出量）心输出量）Cardiac output=stroke volume heart ratestroke volume(ml)ventricular end

9、 diastolic volume(ml)100%EF=u Cardiac index（心脏指数）（心脏指数）Cardiac output(L)Body surface area(m2)CI=5-6(L)1.6-1.7(m2)=3.0 3.5 L/min/m2CI:10 years old:4 normal adult 3 80 years old 2 u Stroke work（每搏功，搏功）（每搏功，搏功）Stroke work(J)=stroke volume(L)ejection pressure+kinetic energy of blood flow 心脏作功量心脏作功量心室收缩一

10、次所做的机械功称为搏功W=PdV（压力-容积功）1/2v2dm（动力功）V2为舒张期末容量，V1为收缩期末容量，P为心室内压，V为心室容量 v为血流速度，m为射出血液的质量 W=PV1/2mv2 P为主动脉平均血压，V 为每搏输出量，v为平均血流速度 剧烈运动时m和v显著增大，动力功不能忽略 W=PVv2v1 心脏心脏作功效率（外功作功效率（外功/心脏耗氧量）心脏耗氧量）心脏消耗内能（主要通过有氧代谢）外能 热（降低作功效率）功 内功（非有用功：等容收缩、心率过快等）外功（和泵血直接有关的有用功）容量功：内功所占比例低，效率高压力功：内功所占比例高，效率低 如动脉压升高，心室扩大 Sectio

11、n 4 Cardiac Reserveu The capacity of cardiac output of a healthy adult:At rest:5 L/minMaximum:25-30 L/minMaximum of a well-trained athlete:35 L/minu The components of cardiac reserve Stroke volume reserve:At rest:70 ml Maximum:105-110 ml(including end diastolic volume reserve 25 ml,end systolic volu

12、me reserve 15-20 ml)Heart rate reserve Maximal HR:160-180 beats/min Too fast HR will decrease the cardiac outputSection 5 Factors that affect cardiac pumping functionu Preload（前负荷）（前负荷）Cardiac preload can be reflected by the ventricular end diastolic pressure,or,initial length(初长度）初长度）.Heterometric

13、autoregulation(Frank-Starling mechanism of the heart)(异长自身调节异长自身调节）：）：The greater the heart muscle is stretched during filling,the greater the force of contraction and the greater the quantity of blood pumped into the aorta.In other words,within the physiologic limits,the heart pumps all the blood t

14、hat comes to it without allowing excessive damming of blood in the veins.Ventricular function curve reflects the relationship between preload and pumping function.The curves do not have downward branchThe mechanisms of Frank-Starling law:(1)The effective overlapping degree of thick filaments and thi

15、n filaments of the sarcomere;(2)The affinity of troponin to Ca2+depends on the length of muscle.The preload is affected by venous retuning volume and end systolic ventricular volume:Four factors determine the venous retuning volume:ventricular filling time venous blood retuning speed The pressure of

16、 pericardial cavity The compliance of the ventricleu Afterload（后负荷）（后负荷）Cardiac afterload can be reflected by the stretching force of the ventricular wall at systole,or the peripheral resistance(外周阻力）外周阻力）.An increase in afterload will decrease cardiac outputu Cardiac contractility（心肌收缩能力）（心肌收缩能力）An

17、 intrinsic factorAffected by neurohormonal factorsIndependent of pre-or afterloadu Heart rate（心率）（心率）正常心脏 心脏扩大 Role of atria in the pumping funtion of heart1.As a tract of blood returning Increased ventricular pressure Dysfunction of atrial contraction Decrease in atrial compliance Decrease in veinous blood retuning Increase in atrial pressure2.As a primary pump(初级泵)(主动充盈作用,在心室被动充盈障碍时尤为重要)结束语结束语谢谢大家聆听！谢谢大家聆听！41