Blood is composed of blood cells suspended in blood plasma. Vertebrate blood is bright red when its hemoglobin is blood orange preserves and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin.

Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Blood is circulated around the body through blood vessels by the pumping action of the heart.

You can help by adding to it. Left tube: after standing, the RBCs have settled at the bottom of the tube. Red blood cells contain the blood’s hemoglobin and distribute oxygen. The blood plasma volume totals of 2. The term serum refers to plasma from which the clotting proteins have been removed.

Most of the proteins remaining are albumin and immunoglobulins. Blood pH is regulated to stay within the narrow range of 7. Extra-cellular fluid in blood that has a pH below 7. Human blood is typical of that of mammals, although the precise details concerning cell numbers, size, protein structure, and so on, vary somewhat between species. Red blood cells of non-mammalian vertebrates are flattened and ovoid in form, and retain their cell nuclei.

Additional return flow may be generated by the movement of skeletal muscles, which can compress veins and push blood through the valves in veins toward the right atrium. The blood circulation was famously described by William Harvey in 1628. Healthy erythrocytes have a plasma life of about 120 days before they are degraded by the spleen, and the Kupffer cells in the liver. The liver also clears some proteins, lipids, and amino acids. The kidney actively secretes waste products into the urine.