Page 233 - Saunders Comprehensive Review For NCLEX-RN

CHAPTER 8

Fluids and Electrolytes

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Priority Concepts
Cellular Regulation; Fluid and Electrolytes

I. Concepts of Fluid and Electrolyte Balance
A. Electrolytes
1. Description: An electrolyte is a substance that, on
dissolving in solution, ionizes; that is, some of its
molecules split or dissociate into electrically charged
atoms or ions (Box 8-1).
2. Measurement
a. The metric system is used to measure
volumes of fluids—liters (L) or
milliliters (mL).
b. The unit of measure that expresses the
combining activity of an electrolyte is
the milliequivalent (mEq).
c. One milliequivalent (1 mEq) of any
cation always reacts chemically with
1 mEq of an anion.
d. Milliequivalents provide information
about the number of anions or cations
available to combine with other anions
or cations.
B. Body fluid compartments (Fig. 8-1)

1. Description
a. Fluid in each of the body compartments
contains electrolytes.
b. Each compartment has a particular
composition of electrolytes, which
differs from that of other
compartments.
c. To function normally, body cells must
have fluids and electrolytes in the right
compartments and in the right
amounts.

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