Match the effects, labelled a. through c., with the change(s). (Options may be used more than once or not at all.)
-increasing the radius of a vessel

Question

Quizplus · Accepted Answer

When the radius of a vessel increases, there is more space for blood to flow through, which means there is less resistance to blood flow. According to Poiseuille's law, blood flow is directly proportional to vessel radius, so increasing the radius would increase blood flow.

Answer: B 
 When the radius of a vessel decreases, there is less space for blood to flow through, which means there is more resistance to blood flow. According to Poiseuille's law, blood flow is inversely proportional to vessel radius to the fourth power, so decreasing the radius would decrease blood flow.

Answer: C 
 The radius of a vessel is a major determinant of blood flow, so changing it will always have an effect on blood flow. There is no scenario in which changing the radius of a vessel would have no effect on blood flow.

Match the Effects, Labelled A