Which Factor Influences Resistance to Blood Flow

Question

Which factor influences resistance to blood flow?
A) blood viscosity
B) blood volume
C) tension of the muscles in the wall of the blood vessels
D) both A and C

Accepted Answer

Both blood viscosity and tension of the muscles in the wall of the blood vessels can affect resistance to blood flow. Blood viscosity refers to how thick or sticky the blood is, and the thicker the blood, the more resistance there is to blood flow. Tension in the muscles of the blood vessel walls can also affect resistance by narrowing or widening the diameter of the blood vessels. Therefore, the correct answer is D, both A and C. Blood volume, on the other hand, does not directly affect resistance to blood flow, as it is more related to blood pressure.