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Physical principles of hemodynamic and bioreology

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Presentation on theme: "Physical principles of hemodynamic and bioreology"— Presentation transcript:

1 Physical principles of hemodynamic and bioreology

2 The Heart and the Cardiovascular System
(2) Cardiac Mechanics. (1) Cardiac electrophysiology.

3 The Heart: two pumps in series: (1) Pulmonary circulation: propels blood through lungs for exchange of O2 and CO2. (2) Systemic circulation: propels blood to all other tissues or organs of body.

4 Anatomy of the Heart

5 Longitudinal cross section

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7 Basic Hemodynamics

8 Basic Hemodynamics

9 Types of flow Flow of fluid in a cylindrical tube may be laminar of turbulent. Laminar flow: flow in lamina, fluid particles do not move in radial or circumferential direction. In Laminar flow the pressure drop (DP) is proportional to flow.

10 Poiseuille’s law Effect of stenosis degree on resistance

11 Types of flow Turbulent flow: irregular flow of fluid elements. Rapid radial and circumferential mixing. In turbulent flow the pressure drop is approximately proportional to square of flow.

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14 Pressure and Volume in the Circulation
Pressure is pulsatile in the arteries but steady in the capillaries and veins. Pressure falls along the circuit with the greatest fall across arterioles. Volume is greatest in the venous system. At any time most of the blood is in veins

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19 The Cardiac Cycle Arterial Pressure Curve Arterial Pressure
40 Arterial Pressure Curve Isovolumetric Contraction Relaxation 120 100 60 Electrocardiogram Ventricular Pressure Arterial Pressure Approx. Time 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 80 10 AV Valve Opens Closes Semi-Lunar Valve Closes Valve Opens Pressure (mm Hg) Ventricular Systole Atrial Diastole T R P Q S Filling Ejection Phase

20 The cardiac cycle

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23 Relationship of myocardial resting sarcomer length (end-diastolic volume) to developed force (peak systolic ventricular pressure) during ventricular contraction in the intact dog heart

24 Pressure-volume loop

25 Pressure-volume loop C D B A ESV

26 Pressure-volume loop for changing preload

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29 DV C = DP DVa DPa = Ca Compliance: Definition:
In regards to aortic mechanics DV or Dva is stroke volume (SV) and DP or DPa is pulse pressure (PP, or Ps-Pd). DPa = DVa Ca For aorta

30 Aortic Pressure Waveform
Dicrotic Notch Mean Pressure Systolic Pulse Pressure Diastolic 120 100 80 Systole Diastole mm Hg

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