"which is more likely to occur, a change in blood vessel radius or a change in blood vessel length? "

Describe the components in the blood that affect viscosity. Your The viscosity of blood is due to the presence of plasma proteins, white blood cells, red blood cells, and platelets. These elements and plasma proteins create resistance as they slide past one another, increasing resistance to flow.The usual pressure difference between the left and right ventricles is about 100 mmHg. The normal cardiac output (the blood flow in the above equation) is about 5 liters/minute. The total peripheral resistance is about 20 (mmHg*min/liters).Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.

Yes yes yes very good