生物医学工程电子仪器01CardiovascularPhysiology课件

1、Department ofEngineering TechnologyCardiovascular PhysiologysegalewitzProf. Scott SegalewitzCirculatory SystemBlood FlowBlood Flow (continued)Actual blood flow is more complex since resistance is not constant vessel walls are not rigid, and blood is subject to changes in viscosity.Blood Changes in V

2、iscosityViscosity is the resistance to flow due to the internal friction of the fluid. Since blood is essentially a suspension of particles (blood cells) in a watery liquid (plasma), the viscosity of blood depends on several factors:As flow decreases, viscosity increasesAs the hematocrit increases,

3、viscosity increasesWhen blood reaches arterioles of about 1mm in diameter, the blood cells align along the direction of laminar flow, reducing viscosityIn the capillaries, blood cells squeeze through in single file, increasing apparent viscosityPoiseuilles LawExample ProblemsFind the resistance of a

4、 blood vessel in which the flow rate is 1.7 mL/s at a blood pressure of 6.8 mmHg.Calculate the flow rate in a blood vessel with an average radius of 0.5 mm if the pressure drop over a 20 mm length is 7.2 mmHg and the blood viscosity is 0.01 Poise.Blood FlowIIIQPThe HeartHeart ValvesHeart ValvesTricu

5、spidPulmonaryMitralAorticArterial Blood PressureMeasuring Blood PressureIndirect (non-invasive)Direct (invasive)Indirect Blood Pressure MeasurementIndirect Blood Pressure MeasurementMeasuring Blood PressureMeasuring Blood PressureDirect Blood Pressure MeasurementDirect Blood Pressure MeasurementBloo

6、d PressureBlood Pressure GradientBlood Pressure GradientBlood Flow MeasurementThermodilution methodThermodilution MethodCardiac OutputCardiac Output (simplified)Cardiac Output exampleA special cardiac test fixture enters a thermistor signal that represents a temperature change of 7 C. Find the expec

7、ted cardiac output reading if the instrument is set to measure the following parameters: injectate volume of 10 mL, body temperature of 37 C, and injectate temperature of 35 C. The catheter correction factor, Ct is 52.5, and the computation time is 10 sCardiac OutputArea under the thermodiluition curveWhereCOis cardiac output (L/min)HRis heart rate (beats/min)SVis stroke volume (L/beat)Cardiac IndexCardiac index relates the cardiac output to the size of the patientWhereCI is cardiac index CO is the cardiac outputBSA is the body surface areaBo