Flashcards in Equations Deck (7)
What does the Bernoulli principle describe the relationship between?
Driving pressure and flow velocity.
Pressure is inversely proportional to the square of the velocity. When pressure goes UP, velocity goes DOWN.
What is the applicability of the Bernoulli principle to the CV system?
Important in determining pressure drops across obstructions to blood flow. By measuring changes in velocity, can extrapolate differences in pressure; can determine severity of stenosis in diseased valve or artery.
What is the LaPlace relationship?
Relationship between wall force, transmural pressure, and radius. Tension = (pressure x radius)/2*(wall thickness). As radius gets bigger, require greater wall force (tension) to maintain the same pressure within the chamber.
What is the applicability of the LaPlace relationship to the CV system?
Determines the risk of rupture of aneurysms
Describes the wall thickness response to maintain pressure.
What is the Poiseulle relationship?
What does it mean?
Describes relationship between pressure drop, flow of fluid in a tube in relation to fluid's viscosity, and tube's diameter and length.
Flow = *Change in Pressure X Pi radius ^4)(*8*viscosity*length).
Biggest takehome is that radius is the most important variable; small changes in radius correspond to flow change to the 4th power. Also shows that as blood becomes more viscous, flow is impaired.
What is Ohm's law as applied to cardiology?
Flow = Pressure/Resistance.