Equations

Question 1

What does the Bernoulli principle describe the relationship between?

Answer 1

Driving pressure and flow velocity.

Pressure is inversely proportional to the square of the velocity. When pressure goes UP, velocity goes DOWN.

Question 2

What is the applicability of the Bernoulli principle to the CV system?

Answer 2

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.

Question 3

What is the LaPlace relationship?

Answer 3

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.

Question 4

What is the applicability of the LaPlace relationship to the CV system?

Answer 4

Determines the risk of rupture of aneurysms

Describes the wall thickness response to maintain pressure.

Question 5

What is the Poiseulle relationship?

What does it mean?

Answer 5

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)(8viscositylength).

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.

Question 6

What is Ohm’s law as applied to cardiology?

Answer 6

Flow = Pressure/Resistance.

Question 7

What ‘s reynold’s law?

Answer 7

Determines laminar vs. turbulent blood flow for a particular flow velocity, vessel diameter, and viscosity.