Red blood cell Much of this potential appears to be contributed by the exposed sialic acid residues in the membrane: their removal results in zeta potential of −6.06 mV. When red blood cells undergo shear stress in constricted vessels, they release ATP, which causes the vessel walls to relax and dilate so as to promote normal blood flow. When their hemoglobin molecules are deoxygenated, red blood cells release S-nitrosothiols, which also act to dilate blood vessels, thus directing more blood to areas of the body depleted of oxygen. Red blood cells can also synthesize nitric oxide enzymatically, using L-arginine as substrate, as do
Vascular remodelling in the embryo early cardiovascular flow, such as preventing the entry of red blood cells into blood plasma, thereby lowering viscosity and associated shear stresses. Starch can also be injected into the blood stream in order to increase viscosity and shear stress. Studies have shown that vascular remodelling in the embryo proceeds without the presence of erythrocytes, which are responsible for oxygen delivery. Therefore, vascular remodelling does not depend on the presence of oxygen and in fact occurs before perfused tissues require oxygen delivery. However, it is still unknown whether or not other nutrients or genetic factors may have promotional effects on vascular