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CHAPTER 4 CIRCULATION 血液循环

CHAPTER 4 CIRCULATION 血液循环. Prof. Wang Ting huai Department of Physiology. Section 2 Cardiac Pump Function 心脏的泵血功能. Ⅰ Cardiac cycle 心动周期. The cardiac cycle includes two phases:systole and diastole ,which forms into one mechanical activity cycle.

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CHAPTER 4 CIRCULATION 血液循环

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  1. CHAPTER 4 CIRCULATION血液循环 Prof. Wang Ting huai Department of Physiology

  2. Section 2 Cardiac Pump Function心脏的泵血功能

  3. ⅠCardiac cycle心动周期 The cardiac cycle includes two phases:systole and diastole ,which forms into one mechanical activity cycle. 心动周期:心脏一次收缩和舒张构成一个机械活动周期，称为心动周期。 The heart rate of average adult man is about 75/min,every cardiac cycle continues about 0.8s. 正常成年人心率平均每分钟75次，心动周期持续0.8s。

  4. A.Features of cardiac mechanical activation心脏机械活动特征 ⒈ Atrium and ventricle contract and relax in order 心房和心室依一定的次序收缩和舒张 ⒉ Diastole Period＞ Systole Period 舒张期时程 > 收缩期时程 ⒊ HR ↑ → diastole ↓↓, systole ↓ HR ↓ → diastole ↑↑, systole ↑ 心率↑ → 舒张期↓↓, 收缩期↓ 心率 ↓ → 舒张期↑↑, 收缩期↑

  5. Contraction or relaxation →changes in pressure → opening or closing of valves → direction of blood flow →the change of the volume of atria and ventricle 心肌收缩或舒张→压力改变 → 瓣膜开或关 → 一定方向的血流，房室容积改变

  6. 1.心房收缩期 2.等容收缩期 3.快速射血期 4.减慢射血期 5.等容舒张期 6.快速充盈期 7.减慢充盈期 AO与AC： 主动脉瓣 开启和关闭 MO和MC： 半月瓣 开启和关闭

  7. B.Mechanical events during the cardiac cycle心动周期中的机械变化 1、 Left ventricular ejection and filling event 左室的射血和充盈过程

  8. 心房收缩期 等容收缩期 快速射血期 减慢射血期 等容舒张期 快速充盈期 减慢充盈期 心肌 状态 房收缩 有张力无缩短 室收缩 室收缩 室舒张 室舒张 室舒张房收缩 压力 改变 房>室 主>室 房<室 主>室 房<室 主<室 房<室 主>室 房<室 主>室 房>室 主>室 房>室 主>室 瓣膜 情况 二尖瓣开 半月瓣关 关 关 关 开 关 开 关 关 开 关 开 关 血流 方向 房 室 无 室 主 室 主 无 房 室 房室 房室 容积 房↓ 室↑ 房－ 室－ 室↓↓ 室↓ 室－ 室↑↑ 房↓ 室↑ 持续 时间 0.1 s 0.05 s 0.10 s 0.15 s 0.06~ 0.08s 0.11 s 0.22 s

  9. a. Atrial systole ：心房收缩期 bicuspid valve open二尖瓣开放 semilunar valve closed半月瓣关闭 Ap>Vp，AOp>Vp， 心房收缩，血液从心房 心室。

  10. Characteristic: Atrium contracts,the intra-atrial pressure increases and the filling of left ventricle keep climbing .This phase lasts about 0.1s. 特点：心房收缩，房内压增高，左心室充盈量进一步增加。这一时期持续0.1s。

  11. b. Ventricular systole: 心室收缩期 (1) Isovolume systole等容收缩期 (2) Rapid ejection period 快速射血期 (3) Reduced ejection period减慢射血期

  12. period of isovolumic contraction等容收缩期 bicuspid valve closed二尖瓣关闭 semilunar valve closed半月瓣关闭 Ap<Vp，AOp>Vp， 心室肌强烈收缩，有张力无缩短。 Closure of AV valves :first heart sound 房室瓣关闭：第一心音

  13. Characteristc: The amplitude of intraventricular pressure pressure increases greatly and sharply .This phase lasts about 0.05s. 特点：室内压大幅度升高，且升高速率很快。 这一时相持续 0.05s左右。

  14. （2） period of rapid ejection快速射血相 semilunar valve open 半月瓣开启 bicuspid valve closed二尖瓣关闭 Ap<Vp，Aop<Vp 心室向主动脉快速射血， 室内压迅速上升到峰值。

  15. Characteristic: The time course takes about 1/3 of the whole ejection period ,and the ejection volume takes about 2/3 of the whole ejection volume.This phase lasts about 0.10s. 特点：时间占射血相1/3左右，射血量占总射血量 的2/3左右。持续0.10s左右。

  16. （3） period of slow ejection减慢射血相 semilunar valve open 半月瓣开启 bicuspid valve closed二尖瓣关闭 Ap<Vp，Aop>Vp 心室射血速度减慢， Ap 和Aop都由峰值下降。

  17. Characteristic: The time course takes about 2/3 of the whole ejection period ,about 0.15s.The intraventricular pressure and aortic pressure begins to decrease from peak amplitude gradually. 特点：时间占射血相2/3左右，约0.15s。心室内压 和主动脉压都相应由峰值逐步下降。

  18. c. Ventricular diastole:心室舒张期 (1) Isovolume diastole等容舒张期 (2) Rapid filling period快速充盈期 (3) Reduced filling period减慢充盈期

  19. (1)period of isovolumic relaxation等容舒张相 semilunar valve closed半月瓣关闭 bicuspid valve closed二尖瓣关闭 Ap<Vp，AOp>Vp 心室继续舒张， Vp快速下降，心室容积不变。 Closure of aortic valves and pulmonary valves : second heart sound 主动脉瓣和肺动脉瓣关闭：第二心音

  20. Characteristc: The intraventricular pressure pressure decreases sharply .This phase lasts about 0.06s-0.08s . 特点：心室内压急剧下降，心室容积保持不变。持续时间约 0.06s-0.08s。

  21. (2) period of rapid filling快速充盈相 bicuspid valve open二尖瓣开启 semilunar valve closed 半月瓣关闭 Ap > Vp，AOp>Vp 血液快速进入心室，心室容积迅速增大。

  22. Characteristic: The phase takes 1/3 of diastoleperiod ,lasts about 0.11s .The filling volume takes about 2/3 of the whole filling volume . 特点：占舒张期的前1/3，占总充盈量的2/3，持续时间约 0.11s。

  23. (3) period of reduced filling减慢充盈相 bicuspid valve open二尖瓣开启 semilunar valve closed 半月瓣关闭 Ap > Vp，AOp>Vp 血液缓慢流入心室，心室容积进一步扩大。

  24. Characteristic: The filling volume takes about 2/3 of the whole filling volume .Which lasts about 0.22s. Following this phase the cardiac enters into next cardiac cycle. 特点：占总充盈量的1/3，持续时间约 0.22s。此后心脏进入下一个心动周期。

  25. B, Left atrial pressure changesduring the cardiac cycle心动周期中左心房压力变化 • ascensus wave:a wave, c wave, v wav 上升波：a 波、c波 、v波 a 波: 心房收缩，房内压升高 c 波：心室开始收缩，房室瓣凸向心房腔， 房内压轻度升高。 v 波： 静脉血回流，房内压升高。

  26. descensus wave: x wave ,y wave 下降波：x波、y波 x波：左心室继续射血，体积缩小， 心房容积趋于扩大， 房内压下降。 y波：房室瓣开放，血液流入心室， 房内压下降。

  27. II. Evaluation of cardiac pump function:心脏泵功能的评估 1. Stroke volume 每搏输出量，约为70ml 2.Cardiac output = stroke volume ×heart rate 每分输出量或心输出量 = 每搏输出量 × 心率， 约为 5L / min (4.5 - 6.0L / min )。

  28. 3.Cardiac index 心指数 Cardiac index is the cardiac output per square meter of body surface area，by which the cardiac outputs of different –sized people can be compared with one another，about 3.0～3.5L/(min·m2). 心指数是单位体表面积的心输出量,可用以比较不同体表面积者的心输出量，约为3.0~3.5L/(min·m2)。 Cardiac index = cardiac output /area of body surface 心指数＝心输出量/体表面积

  29. 4. Ejection fraction (EF) 射血分数 Ejection fraction (EF): SV EDV-ESV EF = ——— = —————— EDV EDV 搏出量 射血分数 = —————— 舒张末容积 舒张末容积 – 收缩末容积 = ———————————— 舒张末容积 约为55%~65%

  30. 5. Cardiac work心脏做功量 Stroke work =Pressure - volume work + kinetic energy 每搏功 = 压力 - 容积功+动力功 a. pressure-volume work / beat = Force ×Distance F×D = (P×A) ×D =P (A×D) = P×ΔV压力容积功＝压力×距离= (压强×面积) ×距离 =压强(面积×距离) =压强×体积

  31. b. Kinetic energy: 1/2mV2 , 2-4% of cardiac work 动力功： 1/2mV2 ，占心脏做功的2-4% 每搏功＝搏出量×射血压力 射血压力＝平均动脉压＝舒张压＋1/3脉压 c. Mechanical efficiency of heart = P×ΔV / E 心脏的机械效率=压力×体积改变/化学能消耗 （E: chemical energy expenditure，化学能消耗）

  32. III.Regulation of cardiac output心输出量的调节 Cardiac output = SV × HR 心输出量 = 搏出量 × 心率 significance:意义 • To meet the need of tissues under different conditions 满足不同条件下的组织需要

  33. To keep cardiac output balance with cardiac filling 保持心输出量与心脏充盈平衡 • To match the output of the right and left ventricle 匹配右室左室的输出量

  34. Determinants of stroke volume： 搏出量的决定因素： • initial length (pre-load) －heterometric autoregulation 初长度 （前负荷）－异长自身调节 • Contractility－homometric autoregulation 收缩能力－等长自身调节 • after-load 后负荷

  35. A. Effect of pre-load on cardiac output前负荷对心输出量的影响－异长自身调节 Frank-Starling Mechanism - Frank- Starling机制 During one specific scope，the bigger the LVEDV,the longer the initial length, and the stronger the strength of the cardiac contraction ，the larger the stoke volume and stoke work . 在一定范围内，心室舒张末期容积（压力）越大， 初长度越长，收缩力量越强，搏出量和搏功越大。

  36. 1.The principle of Frank- Starling mechanismFrank- Starling机制产生原理 Before the initial length of ventricular increases into the optimum level, the longer the initial length ,the larger the amount of overlap between thick and thin filaments ,and the more crossbridge links when activated ,the bigger the contraction intensity of sarcomere.As a result ,the contraction intensity of the whole ventricular and the stroke volume increase.

  37. 在心室初长度达到最适水平之前，随着心肌细胞肌小节的初长度的增加，使粗、细肌丝有效重叠的程度增加，因而激活时可能形成的横桥连接的数目相应增加，肌小节的收缩强度增加，其结果是整个心室收缩强度增加，搏出量增加。在心室初长度达到最适水平之前，随着心肌细胞肌小节的初长度的增加，使粗、细肌丝有效重叠的程度增加，因而激活时可能形成的横桥连接的数目相应增加，肌小节的收缩强度增加，其结果是整个心室收缩强度增加，搏出量增加。

  38. The length – tension curve of skeletal muscle骨骼肌长度-张力曲线

  39. The left to optimal length, Tmax increases as initial length increases. 达到最适初长度以前，最大张力随初长度的增加而增加。 The right to optimal length,Tmax decreases as initial length increases. 达到最适初长度以后，最大张力随初长度的增加而减小。

  40. Ventricular function curve心室功能曲线 12–15mmHg： 最适前负荷 5 – 6mmHg： 正常情况 15-20mmHg: 趋于平坦 >20mmHg: 曲线并不下降

  41. Feature of ventricular function curve：心室功能曲线的特征 a. Optimal pre-load (LVEDP) is 12–15mmHg， Under normal condition, LVEDP is 5 – 6 mmHg. 最适前负荷（左室舒张末压）为12–15mmHg， 正常情况下为5 – 6mmHg。 b. At the left to optimal pre-load, SV↑as LVEDP↑. 在左室达到最适前负荷前，搏出量随左室舒张末压的增加而增加。

  42. c. At LVEDP 15 – 20 mmHg ,the curve still flat. 在左室舒张末压为15 – 20 mmHg 时，曲线趋于 平坦。 d. At LVEDP ＞20 mmHg , curve does not decline due to small distensibility of cardiac muscle. 在左室舒张末压＞20 mmHg时，由于心肌可扩张能力小，曲线并不下降。

  43. LVEDP is 7mmHg, sarcomere length is 2.2m. 左室舒张末压为7 mmHg，肌小节长度是2.2m。 LVEDP is as high as 30mmHg，sarcomere length is still 2.2m. 左室舒张末压高达30mmHg时，肌小节长度仍是2.2m。

  44. Small distensibility and big passive tension due to cardiac connective tissue. 较小的可扩张性和较大的静息张力与心脏的结缔 组织有关 • Ability to resist stretch of myocardium at filling pressure. 在充盈时防止心肌过度牵张 • A safety factor against overloading of heart in diastole. 在舒张期防止心脏负荷过重

  45. 骨骼肌和心肌长度－张力曲线比较 骨骼肌 心肌 安静状态最适初长度左侧升支段, 偏离最适初长 初长度储备 很小 较大 收缩功能 调节范围 很窄 很宽

  46. 2. The physiological functions of Frank- Starling mechanism Frank- Starling机制的生理意义 a.Balance the injection volume of ventricular and the venous return 使心室射血量与静脉回心血量相平衡 b.Keep the cardiac output of the left and right ventriculars equal 维持左右心室的心输出量相等

  47. 3. The main function of Frank- Starling mechanism Frank- Starling机制的主要作用 The main function of Frank- Starling mechanism is to carry out the subtle regulation of stroke volume.when undertaking continuous and intense physical labor , there is a great demand of increase in stroke volume. The mechanism of Frank- Starling law no longer play a role in this process ,and it’s mainly depend on the regulation of cardiac muscle contractility.

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