159
luids and electrolytes are present in body cells, in the
tissue spaces between the cells, and in the blood that
fills the vascular compartment. Body fluids transport
gases, nutrients, and wastes; help generate the electri-
cal activity needed to power body functions; take part
in the transforming of food into energy; and otherwise
maintain the overall function of the body. Although fluid
volume and composition remain relatively constant in
the presence of a wide range of changes in intake and
output, conditions such as environmental stresses and
disease can impair intake, increase losses, and otherwise
interfere with mechanisms that regulate their volume,
composition, and distribution.
This chapter is divided into five sections: composition
and compartmental distribution of body fluids; disor-
ders of sodium and water balance; disorders of potas-
sium balance; disorders of calcium, phosphorus, and
magnesium balance; and disorders of acid–base balance.
Composition and
Compartmental Distribution
of Body Fluids
Body fluids are distributed between the intracellular
and extracellular fluid compartments.
1–3
The
intracel-
lular fluid (ICF) compartment¸
which consists of the
F
Integrative Body
Functions
2
U N I T
Composition and Compartmental Distribution of Body
Fluids
Movement of Body Fluids Between Compartments
Dissociation of Electrolytes
Osmosis and Tonicity
Compartmental Distribution of Body Fluids
Capillary/Interstitial Fluid Exchange
Edema
Third-Space Accumulation
Water and Sodium Balance
Regulation of Water Balance
Regulation of Sodium Balance
Mechanisms of Water and Sodium Regulation
Thirst and Disorders of Thirst
Antidiuretic Hormone and Disorders of
Antidiuretic Hormone
Disorders of Water and Sodium Balance
Isotonic Fluid Volume Deficit
Isotonic Fluid Volume Excess
Hyponatremia
Hypernatremia
Potassium Balance
Regulation of Potassium Balance
Disorders of Potassium Balance
Hypokalemia
Hyperkalemia
Calcium, Phosphorus, and Magnesium Balance
Disorders of Calcium Balance
Regulation of Calcium Balance
Hypocalcemia
Hypercalcemia
Disorders of Phosphorus Balance
Regulation of Phosphorus Balance
Hypophosphatemia
Hyperphosphatemia
Disorders of Magnesium Balance
Regulation of Magnesium Balance
Hypomagnesemia
Hypermagnesemia
Disorders of Parathyroid Hormone
Hypoparathyroidism
Hyperparathyroidism
(continued on page 160)
8
C h a p t e r
Disorders of
Fluid, Electrolyte,
and Acid–Base
Balance
