Blood flow is the flow of blood in the cardiovascular system. It is described by the Ohm's law and approximately by Hagen-Poiseuille's law (because it is accurate only for Newtonian fluids, while blood is not Newtonian and its flow can be described as laminar only in smaller vessels, elsewhere it is turbulent). The upper equation is Ohm's law, you get the Hagen-Poiseuille's law if you insert the lower in it (it is also written in its own article, see link above): Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... The circulatory system or cardiovascular system is the organ system which circulates blood around the body of most animals. ... Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or Voltage drop V between the ends of a conductor and the current I flowing through the conductor are proportional at a given temperature: The equation yields the proportionality constant R, which is the electrical... The Poiseuilles law (or the Hagen-Poiseuille law also named after Gotthilf Heinrich Ludwig Hagen (1797-1884) for his experiments in 1839) is the physical law concerning the voluminal laminar stationary flow ΦV of incompressible uniform viscous liquid (so called Newtonian fluid) through a cylindrical tube with the constant... A Newtonian fluid is a fluid in which shear stress is linearly proportional to the velocity gradient in the direction perpendicular to the plane of shear. ... Laminar flow (bottom of pic) and turbulent flow (top of pic) over a submarine hull. ... Turbulent flow around an obstacle; the flow further away is laminar Laminar and turbulent water flow over the hull of a submarine Turbulence in the tip vortex from an airplane wing In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by low momentum diffusion, high momentum convection...

where:

In the last equation it is important to note that blood flow changes with the fourth power with change of radius. This is important in angioplasty, as it enables the increase of blood flow with balloon catheter to the deprived organ significantly with only a small increase in radius of a vessel. Angioplasty is the mechanical dilation of an artery that has been obstructed, generally due to atheroma (the lesion of atherosclerosis). ... Catheter disassembled In medicine, a catheter is a tube that a health professional may insert into part of the body. ...