Channichthyidae rare and defunct. Oxygen is dissolved in the plasma and transported throughout the body without the hemoglobin protein. The fish can live without hemoglobin because of their low metabolic rates and the high solubility of oxygen in water at the low temperatures of their environment (the solubility of a gas tends to increase as temperature decreases). However, the oxygen-carrying capacity of their blood is less than 10% that of their relatives with hemoglobin. Myoglobin, the oxygen-binding protein used in muscles, is absent from all icefish skeletal muscles. In 10 species, myoglobin is found in the heart muscle, specifically ventricles. Loss
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