Question

The heart requires a continuous flow of blood maintain normal function. The average length of the mid left anterior descending coronary artery is 11 cm and the average diameter is 4.6 mm. The necessary blood flow through this artery is 127 mL/min. Calculate the decrease in pressure along this artery.

b. If plaque deposits reduce the diameter of this artery to 2.6 mm, what would be the new decrease in pressure?

Answer 1

We can use Hagen poiseuille equation

P = 8QnL / r⁴

where, r is radius , L is length, n is viscosity of blood

Q = 127 mL / min = 2.1167e-6 m³ / s

r = 4.6 / 2 = 2.3e-3 m

so,

P = 8 *  2.1167e-6 * 3.015e-3 * 0.11 / * 2.3e-3⁴

P = 63.88 Pa

_____________________

now, when d = 2.6 mm , r = 1.3e-3 m

so,

P = 625.9 Pa