Which of the following changes would most increase the resistance to blood flow in a blood vessel?

Question

Quizplus · Accepted Answer

The resistance to blood flow in a blood vessel depends on its diameter, length, and viscosity of blood. According to Poiseuille's Law, the resistance is inversely proportional to the fourth power of the radius (diameter) of the vessel. Therefore, halving the diameter of the vessel will increase the resistance to blood flow the most. Doubling the diameter of the vessel will decrease the resistance the most. Halving or doubling the length of the vessel will change the resistance proportionally but not as significantly as changing the diameter. Hematocrit, which is the percentage of red blood cells in a given volume of blood, affects the viscosity of blood but not the diameter or length of the vessel. Therefore, decreasing the hematocrit from 50% to 40% will not significantly change the resistance to blood flow.

Which of the Following Changes Would Most Increase the Resistance