Chapter 3 2025 Latest Update
Questions And Answers
,1. Why are infants most susceptible to significant losses in total body water?
a. High body surface-to-body size ratio
b. Slow metabolic rate
c. Kidneys are not mature enough to counter fluid losses
d. Inability to communicate adequately when he or she is thirsty - ANS-ANS: C
Renal mechanisms that regulate fluid and electrolyte conservation are often not mature enough to
counter the losses; consequently, dehydration may rapidly develop. Infants can be
susceptible to changes in total body water because of their high metabolic rate and the turnover of body
fluids caused by their greater body surface area in proportion to their total
body size. An infant's ability to communicate is limited and caregivers must become adept at
reading their signals.
2. Why does obesity create a greater risk for dehydration in people?
a. Adipose cells contain little water because fat is water repelling.
b. The metabolic rate of obese adults is slower than the rate of lean adults.
c. The rate of urine output of obese adults is higher than in lean adults.
d. The thirst receptors of the hypothalamus do not function effectively. - ANS-ANS: A The
percentage of total body water (TBW) varies with the amount of body fat and age. Because fat is water
repelling (hydrophobic), very little water is contained in adipose cells.
Individuals with more body fat have proportionately less TBW and tend to be more susceptible to fluid
imbalances that cause dehydration.
3. A patient's blood gases reveal the following findings: pH 7.3; bicarbonate (HCO3) 27 mEqL;
carbon dioxide (CO2) 58 mm Hg. What is the interpretation of these gases?
a. Respiratory alkalosis
b. Metabolic acidosis
c. Respiratory acidosis
d. Metabolic alkalosis - ANS-ANS: C
The values provided in this question characterize only acute uncompensated respiratory acidosis.
Respiratory acidosis is characterized by a low pH and high CO2. Alkalosis is characterized by higher
than normal pH. A metabolic acidosis would have a lower than normal pH with a bicarbonate
concentration of <22 mEq/L.
4. Water movement between the intracellular fluid (ICF) compartment and the
extracellular fluid
(ECF) compartment is primarily a function of what?
, a. Osmotic forces
b. Plasma oncotic pressure
c. Antidiuretic hormone
d. Hydrostatic forces - ANS-ANS: A
The movement of water between the ICF and ECF compartments is primarily a function of
osmotic forces.
5. In addition to osmosis, what force is involved in the movement of water between the plasma
and interstitial fluid spaces?
a. Oncotic pressure
b. Buffering
c. Net filtration
d. Hydrostatic pressure - ANS-ANS: D
Water moves between the plasma and interstitial fluid through the forces of only osmosis and
hydrostatic pressure, which occur across the capillary membrane. Buffers are substances that
can absorb excessive acid or base to minimize pH fluctuations. Net filtration is a term used to
identify fluid movement in relationship to the Starling hypothesis. Oncotic pressure encourages water to
cross the barrier of capillaries to enter the circulatory system.
6. Venous obstruction is a cause of edema because of an increase in which pressure?
a. Capillary hydrostatic
b. Interstitial hydrostatic
c. Capillary oncotic
d. Interstitial oncotic - ANS-ANS: A
Venous obstruction can increase the hydrostatic pressure of fluid in the capillaries enough to
cause fluid to escape into the interstitial spaces. The remaining options are not causes of
edema resulting from venous obstruction.
7. At the arterial end of capillaries, why does fluid move from the intravascular space into the
interstitial space?
a. Interstitial hydrostatic pressure is higher than the capillary hydrostatic pressure.
b. Capillary hydrostatic pressure is higher than the capillary oncotic pressure.
c. Interstitial oncotic pressure is higher than the interstitial hydrostatic pressure.
d. Capillary oncotic pressure is lower than the interstitial hydrostatic pressure. - ANS- ANS: B
At the arterial end of capillaries, fluid moves from the intravascular space into the interstitial
because capillary hydrostatic pressure is higher than the capillary oncotic pressure.
Questions And Answers
,1. Why are infants most susceptible to significant losses in total body water?
a. High body surface-to-body size ratio
b. Slow metabolic rate
c. Kidneys are not mature enough to counter fluid losses
d. Inability to communicate adequately when he or she is thirsty - ANS-ANS: C
Renal mechanisms that regulate fluid and electrolyte conservation are often not mature enough to
counter the losses; consequently, dehydration may rapidly develop. Infants can be
susceptible to changes in total body water because of their high metabolic rate and the turnover of body
fluids caused by their greater body surface area in proportion to their total
body size. An infant's ability to communicate is limited and caregivers must become adept at
reading their signals.
2. Why does obesity create a greater risk for dehydration in people?
a. Adipose cells contain little water because fat is water repelling.
b. The metabolic rate of obese adults is slower than the rate of lean adults.
c. The rate of urine output of obese adults is higher than in lean adults.
d. The thirst receptors of the hypothalamus do not function effectively. - ANS-ANS: A The
percentage of total body water (TBW) varies with the amount of body fat and age. Because fat is water
repelling (hydrophobic), very little water is contained in adipose cells.
Individuals with more body fat have proportionately less TBW and tend to be more susceptible to fluid
imbalances that cause dehydration.
3. A patient's blood gases reveal the following findings: pH 7.3; bicarbonate (HCO3) 27 mEqL;
carbon dioxide (CO2) 58 mm Hg. What is the interpretation of these gases?
a. Respiratory alkalosis
b. Metabolic acidosis
c. Respiratory acidosis
d. Metabolic alkalosis - ANS-ANS: C
The values provided in this question characterize only acute uncompensated respiratory acidosis.
Respiratory acidosis is characterized by a low pH and high CO2. Alkalosis is characterized by higher
than normal pH. A metabolic acidosis would have a lower than normal pH with a bicarbonate
concentration of <22 mEq/L.
4. Water movement between the intracellular fluid (ICF) compartment and the
extracellular fluid
(ECF) compartment is primarily a function of what?
, a. Osmotic forces
b. Plasma oncotic pressure
c. Antidiuretic hormone
d. Hydrostatic forces - ANS-ANS: A
The movement of water between the ICF and ECF compartments is primarily a function of
osmotic forces.
5. In addition to osmosis, what force is involved in the movement of water between the plasma
and interstitial fluid spaces?
a. Oncotic pressure
b. Buffering
c. Net filtration
d. Hydrostatic pressure - ANS-ANS: D
Water moves between the plasma and interstitial fluid through the forces of only osmosis and
hydrostatic pressure, which occur across the capillary membrane. Buffers are substances that
can absorb excessive acid or base to minimize pH fluctuations. Net filtration is a term used to
identify fluid movement in relationship to the Starling hypothesis. Oncotic pressure encourages water to
cross the barrier of capillaries to enter the circulatory system.
6. Venous obstruction is a cause of edema because of an increase in which pressure?
a. Capillary hydrostatic
b. Interstitial hydrostatic
c. Capillary oncotic
d. Interstitial oncotic - ANS-ANS: A
Venous obstruction can increase the hydrostatic pressure of fluid in the capillaries enough to
cause fluid to escape into the interstitial spaces. The remaining options are not causes of
edema resulting from venous obstruction.
7. At the arterial end of capillaries, why does fluid move from the intravascular space into the
interstitial space?
a. Interstitial hydrostatic pressure is higher than the capillary hydrostatic pressure.
b. Capillary hydrostatic pressure is higher than the capillary oncotic pressure.
c. Interstitial oncotic pressure is higher than the interstitial hydrostatic pressure.
d. Capillary oncotic pressure is lower than the interstitial hydrostatic pressure. - ANS- ANS: B
At the arterial end of capillaries, fluid moves from the intravascular space into the interstitial
because capillary hydrostatic pressure is higher than the capillary oncotic pressure.
