mineral

any naturally occurring nonorganic homogeneous solid substance. There are 19 or more that form the mineral composition of the body; at least 13 are essential to health. These must be supplied in the diet and generally can be supplied by a varied or mixed diet of animal and vegetable products that meet energy and protein needs. For the recommended dietary allowances of common minerals in the United States and Canada, see Appendices 4 and 5. Calcium, iron, and iodine are the ones most frequently missing in the diet. Zinc, copper, magnesium, and potassium are minerals that are frequently involved in disturbances of metabolism. Other essential minerals include selenium, phosphorus, manganese, fluoride, chromium, and molybdenum. Minerals are either electropositive or electronegative; combinations of electropositive and electronegative elements lead to the formation of salts such as sodium chloride and calcium phosphate.

any of a group of hormones elaborated by the cortex of the adrenal gland, so called because of their effects on sodium, chloride, and potassium concentrations in the extracellular fluid. They are the adrenocortical hormones that are essential to the maintenance of adequate fluid volume in the extracellular and intravascular fluid compartments, normal cardiac output, and adequate levels of blood pressure. Without sufficient supply of the mineralocorticoids, fatal shock from diminished cardiac output can occur very quickly.

The principal mineralocorticoid is aldosterone, which accounts for most of the activities of this group of hormones. The primary effects of the mineralocorticoids are increasing the reabsorption of sodium and the secretion of potassium in the renal tubules. Secondary effects are related to the reabsorption of water, serum levels of sodium and potassium, anion reabsorption, and secretion of hydrogen ions. The net result of these activities is maintenance of fluid and electrolyte balance and, therefore, adequate cardiac output.