Acid Base Balance

1. Acid-Base Balance

When we talk about acid-base balance, we are referring to the pH balance (degree of acidity or alkalinity) of substances or of the body. The symbol pH is used after numbers that measure the degree of the acidity or alkalinity of solutions. The acidity or the alkalinity of a solution is determined by the number of hydrogen ions (H + ) it contains. The smaller the pH value of a solution; that is, the smaller the number preceding the symbol pH is, the greater is the acidity of that solution. Likewise, the larger the number in front of the symbol pH is, the greater is the alkalinity of the solution.

Any neutral solution, such as water, will have a pH value of 7.0. Solutions which have a pH value below 7.0 are acidic in nature. Solutions which have a pH value above 7.0 are considered to be alkaline, or basic.

The human body must continuously deal with many different substances in the bloodstream. Each substance has a range of concentration which can vary within certain limits without creating an imbalance of normal bodily functions. Certain substances, such as blood glucose, can vary up to 200%, while certain other substances, such as blood calcium, are constricted to a much narrower range of deviation.

The balance in the blood of acidic and alkaline components can be only moderately altered without
creating a very serious physiological instability. Therefore, it is crucial that the body, while controlling degrees of pH in organs, glands and other areas of the body, simultaneously maintain this strict range of balance in the pH of the blood. The following chart best illustrates the pH ranges of different areas of the body:

The blood is slightly alkaline, with a pH of 7.35 to 7.4. Many of the enzymes that facilitate metabolic reactions operate optimally only in solutions of specific alkalinity. When there is a deviation from this level of alkalinity, whether higher (referred to as alkalosis), or lower (referred to as acidosis), severe malfunctions can occur. These malfunctions are manifested by slower enzymatic reactions, and thus a decrease in synthesis of specialized molecules, such as vitamins, proteins, etc. There is also an impairment of the production of ATP molecules that are needed for energy and are made from glucose.

The major effect of acidosis is disorientation due to the depression of the central nervous system. Inversely, the major effect of alkalosis is extreme nervousness, eventually leading to convulsive reactions, namely tonic spasm. This spasm is referred to as tetany, and usually develops primarily in the musculature of the forearm and face, then spreads over the muscular system of the entire body. Tetany results from over-excitability of the central and peripheral nervous systems due to alkalosis.