Vascular resistance recent results showing the sheath flow surrounding the plug flow in a vessel, the sheath flow size is not neglectible in the real blood flow velocity profile in a vessel. The velocity profile is directly linked to flow resistance in a vessel. The viscosity variations, according to Thurston, are also balanced by the sheath flow size around the plug flow. The secondary regulators of vascular resistance, after vessel radius, is the sheath flow size and its viscosity. Thurston, as well, shows that the resistance R is constant, where, for a defined vessel radius, the value η(δ)/δ is constant in the
Vascular resistance Systemic vascular resistance: 18 x 80 = 1440 dyn·s/cm5. These values are in the normal limits. There are many factors that alter the vascular resistance. Vascular compliance is determined by the muscle tone in the smooth muscle tissue of the tunica media and the elasticity of the elastic fibers there, but the muscle tone is subject to continual homeostatic changes by hormones and cell signaling molecules that induce vasodilation and vasoconstriction to keep blood pressure and blood flow within reference ranges. In a first approach, based on fluids dynamics (where the flowing material is continuous and made of continuous atomic