Poiseuille's Law of Laminar Flow
by Greg Crowther
When you wanna thinka like Poiseuille,
There's a formula you employ.
When the blood flows around and around and around,
The flow rate through a given vessel can be found
As R times R times R times R
(That's R to the fourth)
Times deltaP,
And that's all divided by
Eight over pi
Times the length of the vessel
Times viscosity.
R times R times R times R
(That's R to the fourth)
Times delta P,
And that's all divided by
Eight over pi
Times the length of the vessel
Times viscosity.
A short song, written for BIOL 220 at the University of Washington, about the factors governing blood flow. Ideally, it should be performed with a peppy zydeco feel. In this formulation of Poiseuille's Law, R stands for radius and delta P is the difference in pressure. (Alternatively, the law can be written simply as delta P over resistance. Resistance may also be abbreviated R, so be careful!)
The repetition of "R times R times R times R" emphasizes that blood flow rate is highly sensitive to vessel radius. In addition, the rhyme with "employ" helps people pronounce "Poiseuille," a difficult surname.
