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1、医学英语 心脏nWhat is the circulatory system?nWhat does the CV system do?nInternal and external anatomynCardiac cyclenHeart soundsnConductive system of the heartnBlood vesselsnDiseases of the CVSSerous membraneContinuous withblood vesselsThe Heart: muscle layers and coveringsThe Heart: muscle layers and c
2、overingsConnective tissEndothiliumExternal Heart AnatomyPage44The Heart: ChambersLungsBody cellsOur circulatory system is a double circulatory system. This means it has two parts parts. the right side of the system deals with deoxygenated blood.the left side of the system deals with oxygenated blood
3、.CirculationCoronarycirculationthecirculationofbloodwithintheheart.Pulmonarycirculationtheflowofbloodbetweentheheartandlungs.Systemiccirculationtheflowofbloodbetweentheheartandthecellsofthebody.The Heart: ValvesBicuspid(mitral)Tricuspid(AV)PulmonaryAortic(SL)HowdoestheHeartwork?bloodfromthebodyblood
4、fromthelungsThe heart beat begins when theheart muscles relax and bloodflows into the atria.STEP ONEThe atria then contract andthe valves open to allow bloodinto the ventricles.HowdoestheHeartwork?STEP TWOHowdoestheHeartwork?The valves close to stop bloodflowing backwards.The ventricles contract for
5、cing the blood to leave the heart.At the same time, the atria arerelaxing and once again filling withblood.The cycle then repeats itself.STEP THREEFilling of Heart Chambers the Cardiac CycleCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsThe Heart: Cardiac OutputCopyright 2003
6、Pearson Education, Inc. publishing as Benjamin CummingsCardiac output (CO) total vent blood/minAmount of blood pumped by each side of the heart in one minuteCO = (heart rate HR) x (stroke volume SV)Stroke volumeVolume of blood pumped by each ventricle in one contractionS1- What is it ?closing of the
7、 bicuspid and tricuspid valves. (closure of the AV valves)The Pulmonic and Aortic valves are openingand blood is being forced into the arteriesS2- What is it ?The sounds are because of the closing of the Pulmonic and Aortic valves (closure of the semilunar valves)Conductive SystemActionpotential-ele
8、ctricalimpulsecausingthecontractionofheartmusclecellsThe SA node, or pacemaker, initiates the heartbeat and causes the atria to contract on average every 0.85 seconds. The AV node conveys the stimulus and initiates contraction of the ventricles. The signal for the ventricles to contract travels from
9、 the AV node through the atrioventricular bundle to the smaller Purkinje fibers.ElectrocardiogramnAn electrocardiogram (ECG) is a recording of the electrical changes that occur in the myocardium during a cardiac cycle. nThe P wave occurs just prior to atrial contraction; the QRS complex occurs just
10、prior to ventricular contraction; and the T wave occurs when the ventricles are recovering from contraction.The Vascular SystemCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsBlood Vessels: AnatomyThree layers (tunics)Tunic intimaEndotheliumTunic mediaSmooth muscleTunic externa
11、Mostly fibrous connective tissueConductive SystemCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 11.5nTunica externaOutermost layerelastin and collagenStrengthens, AnchorsnTunica mediaMiddle layerCircular Smooth MuscleVaso-constriction/dilationnTunica intimaInnermost lay
12、erEndotheliumMinimize frictionnLumenArtery/Vein differences（归纳：dtwlv)Arteries(aa.)Veins(vv.)DirectionofflowBlood Away from HeartBlood to HeartPressureHigherLowerWallsTHICKER: Tunica media thicker than tunica externaTHINNER: Tunica externa thicker than tunica mediaLumenSmallerLargerValvesNo valvesVal
13、ves CoronaryarterycirculationPulsePulse pressure wave of bloodMonitored at “pressure points” where pulse is easily palpatedMeasuring Arterial Blood PressureCardiovascular DiseasesnCardiovascular diseases include those that affect the heart and those that affect the peripheral vascular system.nThe he
14、art and blood vessels may be primarily attacked by these diseases or they may be secondarily affected as a consequence of another disease.Risk Factors for Cardiovascular Disease(sdosp)nSmokingnDiabetesnObesity nStressnPhysical InactivitynHigh Blood Pressure 140 (systolic) / 90 (diastolic)Cardiovascular DiseasesnCoronary Artery Disease (CAD)nEndocarditisnPericarditisnRheumatic Heart DiseasenHypertensionnCardiac ArrhythmianCongestive Heart Failure (CHF)nStrokenArteriosclerosisnAneurysm结束语结束语谢谢大家聆听！谢谢大家聆听！38
