Question

A blood vessel is 15 cm long, and has a radius of 4.7 mm. If blood is flowing through it with a volume flow rate of 5 X10-7 m3/s, what is the difference in the pressures at the two ends of the blood vessel? Do NOT assume there is zero viscosity.

Answer 1

Using Poiseuille's equation, Change in pressure is given by:

dP = 8*n*L*Q/(pi*R^4)

Q = Volume flow rate = 5*10^-7 m^3/sec

L = length of blood vessel = 15 cm = .15 m

n = Viscosity of blood = 4*10^-3 Pa-sec

R = radius of vessel = 4.7 mm = 4.7*10^-3 m

dP = Change in pressure = ?

So, Using these values:

dP = 8*4*10^-3*0.15*5*10^-7/(pi*(4.7*10^-3)^4)

dP = 1.5655 Pa

dP = 1.6 Pa = Pressure difference between two ends of vessel

Your value will also depend on the viscosity of blood So If your reference book have different value than the value used by me, let me know through comments

answered by: anonymous