B. Vital Functions of Minerals

Minerals have many vital functions in the body. The skeletons of vertebrate animals are composed chiefly of minerals (nearly all calcium and phosphorus), and minerals are essential constituents of the soft tissues and fluids of the body.

Phosphorus is a vital ingredient in the proteins that characterize the nuclei of all body cells, and also is a component of certain other important proteins such as the casein of milk. The phospholipids, which are phosphorus-containing milk fat-like substances, are essential parts of all living protoplasm. The power of the blood to carry oxygen is due to hemoglobin, the iron-protein compound in the red blood corpuscles.

The acidity and alkalinity of the digestive juices is due to mineral compounds. Thus, the acidity of the gastric juice in the stomach, which is necessary for the action of the enzyme, pepsin, is due to hydrochloric acid, derived from sodium chloride and other chlorides that are present in the blood.

The osmotic pressure which is necessary for the transfer of nutrients and waste products through the cell walls is largely dependent on the concentration of mineral salts in the lymph and in the cells.

A serious lack of calcium in the blood such as may occur in milk fever of cows and in certain advanced cases of rickets is the cause of convulsions and tetany.