Page 239 - Saunders Comprehensive Review For NCLEX-RN

c. A hypotonic solution has less solute
than an isotonic solution, whereas a
hypertonic solution contains more
solute.
6. Active transport
a. If an ion is to move through a
membrane from an area of lower
concentration to an area of higher
concentration, an active transport
system is necessary.
b. An active transport system moves
molecules or ions against
concentration and osmotic pressure.
c. Metabolic processes in the cell supply
the energy for active transport.
d. Substances that are transported actively
through the cell membrane include
ions of sodium, potassium, calcium,
iron, and hydrogen; some of the
sugars; and the amino acids.
H. Body fluid intake and output (Fig. 8-2)

1. Body fluid intake
a. Water enters the body through 3
sources—orally ingested liquids, water
in foods, and water formed by
oxidation of foods.
b. About 10 mL of water is released by the
metabolism of each 100 calories of fat,
carbohydrates, or proteins.
2. Body fluid output
a. Water lost through the skin is called
insensible loss (the individual is
unaware of losing that water).
b. The amount of water lost by
perspiration varies according to the
temperature of the environment and of
the body.
c. Water lost from the lungs is called
insensible loss and is lost through
expired air that is saturated with water
vapor.
d. The amount of water lost from the
lungs varies with the rate and the
depth of respiration.
e. Large quantities of water are secreted
into the gastrointestinal tract, but
almost all of this fluid is reabsorbed.

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