Summary

• Sodium and phosphate are involved in the regulation of extracellular fluid and pH
• Calcium fluoride is found in bone, cartilage, skin and connective tissues (including those of the digestive tract) and aids tissue strength, flexibility and elasticity
• The phosphate buffer system is one of the body’s important mechanisms for maintaining intracellular acid-base balance, in which sodium monohydrogen phosphate and sodium dihydrogen phosphate act as efficient buffers in acid and alkaline conditions respectively
• Calcium fluoride is widely distributed in connective tissue (for example in cartilage, skin, muscles, nerves, valves and sphincters), where it is important for strength, flexibility and elasticity
• The fluoroapatite crystal, composed of calcium and fluoride, is also present in tooth enamel, where its stable structure gives the teeth tremendous strength and enables them to resist acid and caries