Hemodynamics Flashcards
Vascular branching results in an
Increase in total cross sectional area
Fluid mechanics can define
Flow through straight rigid tubes
Cardiovascular syste contains
Non homogenous fluid
Traveling through branched non-rigid tubes
Propelled by pulsatile forces
Hemodynamics
The study of physical conditions governing flow through the vasculature
CO =
(MAP - RAP)/ TPR
Resistance to flow (TPR)) as describes by Poiseullie
R = 8n(viscosity)L/Npier^4
Factors influencing the properties of blood under pressure
Viscosity
Deformabilty
Blood viscosity changes with
Hematocrit, pressure gradients, vessel diameter, and temperature
Fibrinogen in the red blood cells increase in
Sickle cell anemia
Flow of blood through the cardiovascular system requires
Pressure gradients
Flow can be
Laminar or turbulent
Laminar flow
Little mixing of fluid in different layers
Very efficient
Shear stress on the vascular walls is proportional to rate of flow
Turbulent flow
Irregular motion fluid within a tube
Usually associated with murmurs and may be normal or abnormal
Energy in eddies is converted to heat, thus additional pressure is needed to move fluid along during turbulent flow
Increases resistance to flow
Turbulence is predicted by
The Reynold’s number
Re =
V * D * density / viscosity
Is Reynolds is 2000
2000 - turbulent flow
What predispose vessels to turbulent flow
Large vessels, high blood viscosity, low blood viscosity
Total energy
Kinetic energy + potential energy
Bernoulli’s principle
Total energy at one area in a closed system must equal total energy in another area
Contributes to the drop pressure ad velocity between adjacent vascular beds
Bernoulli’s principal applied to aortic stenosis
Decreased lateral pressure
Reduce coronary filling since lateral pressure is important in the continues proposing of blood during early diastole
Bernoulli’s principle applied to aneursym
KE will decrease due to a lower velocity of flow through the region of large diameter
Aneursym
Abnormal dilutions of blood vessel walls resulting from disease of the vessel wall
Total energy
Kinetic energy + potential energy
Bernoulli’s principle
Total energy at one area in a closed system must equal total energy in another area
Contributes to the drop pressure ad velocity between adjacent vascular beds
Bernoulli’s principal applied to aortic stenosis
Decreased lateral pressure
Reduce coronary filling since lateral pressure is important in the continues proposing of blood during early diastole
Bernoulli’s principle applied to aneursym
KE will decrease due to a lower velocity of flow through the region of large diameter
Aneursym
Abnormal dilutions of blood vessel walls resulting from disease of the vessel wall
