Function

The mineral matter in the body serves the most varied ends. It gives solidity to the bones and teeth; its presence in body fluids, such as blood and lymph, imparts to them a certain degree of concentration which is absolutely necessary to the vital processes. Again, minute quantities of mineral matter are invariably present in living cells and are indispensable to their existence. The kind of mineral matter in a given tissue or organ varies according to its function. The bones and teeth owe their stability to salts of calcium (lime) and magnesium, especially the phosphates. The salts which are necessary for the regulation of the body fluids comprise potassium, sodium, calcium and magnesium, especially in the form of chlorides. The substances essential to the active cells as part of their normal structure comprise phosphorus, iron, and sulphur, in the form of organic compounds, along with other salts in small quantities. Phosphorus is found in the nuclei of all cells and is essential for growth. The red corpuscles are rich in iron, and the thyroid gland cells contain considerable iodin. Nearly all cells have traces of sulphur, mainly in the form of protein.

Amount And Kind Of Mineral Matter In The Organism

The mineral matter in the body amounts to about 5 or 6 per cent. by weight, occurring chiefly in the bones. The elements needed in the body can all be found in food.

The chemical elements found in the body comprise hydrogen, oxygen, nitrogen, carbon, phosphorus, sulphur, silicon, fluorin, chlorin, iodin, all of the non-metal type; while of the metals are present sodium, potassium, calcium, magnesium, iron. Traces of manganese, aluminium, possibly also arsenic, are sometimes found. Any substance which exists in the soil may find its way into the body.

There is more calcium (lime) in the body than any other of the metals, while phosphorus exists to a greater extent than any other non-metallic element, exclusive of those which go to form living matter. These elements predominate thus because the bones contain so large an amount of phosphate of lime. Lime is also present to a considerable extent as carbonate. Magnesium phosphate comes next in amount. With the exception of these three bone compounds, mineral matter is present in relatively small quantities.

The sodium and chlorin occur chiefly in the form of sodium chlorid, which is present in all the fluids and solids. The chlorin of hydrochloric acid of the gastric juice comes from the sodium chlorid. Some sodium is also present as carbonate and phosphate, and these two are found in sufficient amount to give the blood and numerous fluids and secretions an alkaline reaction. Potassium occurs mainly in the form of potassium phosphate. Muscle-tissue is rich in this salt.

The sulphur and phosphorus which enter the body in the form of protein in animal food are oxidized to sulphuric and phosphoric acids and these at once combine with bases to form sulphates and phosphates of lime, sodium, etc. Sulphates occur to a slight extent only, while as already stated phosphates are the most important constituents numerically.