Fluid Dynamics Flashcards
What is another word for the measurement of stiffness?
Elasticity
General formula for elasticity
stress/strain
Viscoelasticity
has a changing elasticity, so is not linear
Stress
aka pressure= force/area
Hydrostatic pressure variables
Density, gravity, height of fluid
What is the driving force that moves biological fluids?
Pressure
Perfusion definition
volume and distribution of blood flow
Whole body perfusion
cardiac output
Hydrostatic pressure’s influence on absolute pressure and pressure gradient
Affects pressure inside the vessels, but not the pressure gradient that determines blood flow
Pressure difference between the inside and outside pressures on a vessel
Transmural pressure
What does the body do to counteract constant hypertension?
hypertrophy (increase wall thickness)
Compliance
Reciprocal of elasticity. Strain/stress OR volume/pressure
Flow velocity formula
velocity*area
Viscosity
Slipperiness between layers of a fluid. More=flatter cone, less = more pointy cone.
What are small blood vessel’s impact on viscoity? (Fahraeus-Lindquivst Effect)
Decreased area=decreased velocity, so RBC will migrate to the center while WBCs/platelets migrate to the perimeter
Reynolds number represents what?
Turbulent flow
Bruit
audible sound with stethoscope in an artery
What is a non-invasive test of fetal anemia?
Doppler ultrasound. Low velocity = low hemocrit
Factors affecting viscosity
Hemocrit, plasma proteins, Fahraeus-Lindquivst Effect, RBC deformity, temperature
Factors affecting turbulent flow
Velocity, obstructions/rough surfaces, sharp turns, viscosity of blood
What are length and viscosity’s ipact on resistance?
length (4x’s impact). Viscosity direct impact
Resisters in series (Really simple)
Add together
Resisters in parallell
Add the fractions
Starling resistor
Collapsable vessel
