acid-base balance (redirected from Acid-base homeostasis)

balance /bal·ance/ (bal´ans)

1. an instrument for weighing.

2. equilibrium.

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acid-base balance  a normal balance between production and excretion of acid or alkali by the body, resulting in a stable concentration of H+ in body fluids.

analytical balance  a balance used in the laboratory, sensitive to variations of the order of 0.05 to 0.1 mg.

fluid balance  the state of the body in relation to ingestion and excretion of water and electrolytes.

nitrogen balance  the state of the body in regard to ingestion and excretion of nitrogen. In negative nitrogen b. the amount excreted is greater than the quantity ingested; in positive nitrogen b. the amount excreted is smaller than the quantity ingested.

water balance  fluid b.

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acid-base balance

n.

The state that exists when acidic and basic ions in solution neutralize each other.

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Acid-base balance

The condition that exists when the body's carbonic acid-bicarbonate buffer system is in equilibrium, helping to maintain the blood pH at a normal level of 7.35-7.45.

Mentioned in: Blood Gas Analysis, Electrolyte Disorders

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acid-base balance,

a condition existing when the net rate at which the body produces acids or bases equals the net rate at which acids or bases are excreted. The result of acid-base balance is a stable concentration of hydrogen ions in body fluids. See also acid, base.

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acid-base balance,

n the balance of acid to base necessary to keep the blood pH level normal (between 7.35 and 7.43).

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acid-base balance

a state of equilibrium between acidity and alkalinity of the body fluids; called also hydrogen ion (H+) balance because, by definition, an acid is a substance capable of giving up a hydrogen ion during a chemical exchange, and a base is a substance that can accept it. The positively charged hydrogen ion (H+) is the active constituent of all acids.

Most of the body's metabolic processes produce acids as their end products, but a somewhat alkaline body fluid (pH 7.4) is required as a medium for vital cellular activities. Therefore chemical exchanges of hydrogen ions must take place continuously in order to maintain a state of equilibrium. An optimal pH (hydrogen ion concentration) between 7.35 and 7.45 must be maintained; otherwise, the enzyme systems and other biochemical and metabolic activities will not function normally.

Although the body can tolerate and compensate for slight deviations in acidity and alkalinity, if the pH drops below 7.30, the potentially serious condition of acidosis exists. If the pH goes higher than 7.50, the patient is in a state of alkalosis. In either case the disturbance of the acid-base balance is considered serious, even though there are control mechanisms by which the body can compensate for an upward or downward change in the pH. Shifts in the pH of body fluids are controlled by three major regulatory systems which may be classified as chemical (the buffer systems), biological (blood and cellular activity), and physiological (the lungs and kidneys).

Imbalances of the acid-base ratio are discussed under acidosis and alkalosis. Diagnosis and monitoring of either of these conditions are greatly enhanced by periodic determination of the plasma pH and by blood gas analysis.

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acid-base balance

Acid-base homeostasis Nephrology A physiologic state defined by the pH in the serum, which normally is a tad alkaline; acids CO₂ and molecules containing H+, which are buffered by alkaline substances, primarily HCO₃, with some buffering by phosphate, proteins, Hb, and other substances; ↑ CO₂ or ↓ HCO₃ causes acidosis; conversely, ↓ CO₂ or ↑ HCO₃ causes alkalosis; if the defect is caused by changes in CO₂, it is a respiratory acidosis or respiratory alkalosis; if the defect is caused by changes in HCO₃ levels, it is a metabolic acidosis or metabolic alkalosis; the lungs regulate the levels of CO₂ through changes in the breathing rate; CO₂ is lost with faster breathing and ↑ when breathing slows, which provides fast but temporary regulation of body pH; major, long-term regulation of body pH occurs in the kidneys, which excrete acids, and excrete or create HCO₃ for use in the body