All the other materials that are carried by the blood are carried in the plasma, usually in solution. Plasma contains a high concentration of protein and substances that are insoluble or scarcely soluble in water are carried in the blood bound to these plasma proteins. Basic physics of the flow of fluids including blood A knowledge of the physics of blood flow is essential for understanding how the cardiovascular system works. Flow, which is volume per unit time, must be distinguished from velocity, which is distance per unit time. There are two types of flow, streamline and turbulent.
Turbulent flow is noisy.
Most flow in the cardiovascular system is streamline. Note that it is the fourth power of the radius that determines the flow, so the radius of vessels is a very important factor for regulating blood flow. Poiseuille's Law does not apply exactly to blood flowing through vessels, which are not rigid, but it still is a reasonable approximation. When blood flows there is a layer of plasma with no red cells in it against the wall of the vessel, a phenomenon called axial streaming. Where a small vessel branches from a large one, axial streaming may mean that few red blood cells go down the small vessel.