Page 273 - Saunders Comprehensive Review For NCLEX-RN

CHAPTER 9

Acid-Base Balance

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Priority Concepts
Acid-Base Balance; Oxygenation

I. Hydrogen Ions, Acids, and Bases
A. Hydrogen ions
1. Vital to life because hydrogen ions determine the pH
of the body, which must be maintained in a narrow
range
2. Expressed as pH; the pH scale is determined by the
number of hydrogen ions and goes from 1 to 14; 7 is
considered neutral.
3. The number of hydrogen ions in the body fluid
determines whether it is acid (acidosis), alkaline
(alkalosis), or neutral.
4. The pH of body fluid is between 7.35 and 7.45.
B. Acids
1. Produced as end products of metabolism
2. Contain hydrogen ions
3. Are hydrogen ion donors; they give up hydrogen ions
to neutralize or decrease the strength of an acid or to
form a weaker base.
C. Bases
1. Contain no hydrogen ions
2. Are hydrogen ion acceptors; they accept hydrogen +
ions from acids to neutralize or decrease the strength
of a base or to form a weaker acid.
3–
3. Normal serum levels of bicarbonate (HCO ) are 21 to
28 mEq/L (21 to 28 mmol/L).
II. Regulatory Systems for Hydrogen Ion Concentration in the Blood
A. Buffers
1. Buffers are the fastest-acting regulatory system.
2. Buffers provide immediate protection against changes
in hydrogen ion concentration in the extracellular
fluid.
3. Buffers are reactors that function only to keep the pH
within the narrow limits of stability when too much

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