Question

All of the following will increase blood flow except

Answer 1

Answer:

D. Decreasing vessel diameter

Explanation:

Cardiac output is the amount of blood pumped per unit time by heart. Increased cardiac output corresponds to increased blood pressure which will result in increased blood flow. In vasodilation the smooth muscles within the blood vessels relax making them wide hence decreasing vascular resistance leading to more blood flow. Decreased blood viscosity will also decrease the resistance to blood flow.

Decreasing vessel diameter will not increase the blood flow, it will rather restrict it because there will be more resistance to passage of blood due to small space.