The most important variable that determines resistance to blood flow is
A)the viscosity of blood.
B)the length of the blood vessel.
C)the diameter of the vessel.
D)blood pressure.

Question

Quizplus · Accepted Answer

The diameter or radius of the blood vessel is the most important variable that determines resistance to blood flow. This is due to the fact that resistance to blood flow is inversely proportional to the fourth power of the radius of the vessel according to Poiseuille's law. Therefore, even a slight change in diameter can significantly alter the resistance to blood flow. The viscosity, length, and blood pressure do play a role in resistance to blood flow, but they are not as significant as the diameter of the vessel.

The Most Important Variable That Determines Resistance to Blood Flow