Chapter 3: The Cellular Environment: Fluids and Electrolytes, Acids and Bases

Chapter 3: The Cellular Environment: Fluids and Electrolytes, Acids and Bases

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. Infants are most susceptible to significant losses in total body water because of an infant’s:

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:  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. The inability to communicate their thirst is a problem only when they are poorly cared for.

 

PTS:   1                    REF:   Page 104

 

2. Obesity creates a greater risk for dehydration in people because:

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 the rate of output of lean adults.
d.	The thirst receptors of the hypothalamus do not function effectively.

 

 

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.

 

PTS:   1                    REF:   Page 104

 

3. A patient’s blood gases reveal the following findings: pH, 7.3; bicarbonate (HCO₃) 27 mEq/L; carbon dioxide (CO₂), 58 mm Hg. What is the interpretation of these gases?

a.	Respiratory alkalosis	c.	Respiratory acidosis
b.	Metabolic acidosis	d.	Metabolic alkalosis

 

 

ANS:  C

The values provided in this question characterize only acute uncompensated respiratory acidosis.

 

PTS:   1                    REF:   Pages 129-130

 

4. Water movement between the intracellular fluid (ICF) compartment and the extracellular fluid (ECF) compartment is primarily a function of:

a.	Osmotic forces	c.	Antidiuretic hormone
b.	Plasma oncotic pressure	d.	Hydrostatic forces

 

 

ANS:  A

The movement of water between the ICF and ECF compartments is primarily a function of osmotic forces. (Osmosis and other mechanisms of passive transport are discussed in Chapter 1.)

 

PTS:   1                    REF:   Page 105

 

5. In addition to osmosis, what force is involved in the movement of water between the plasma and interstitial fluid spaces?

a.	Oncotic pressure	c.	Net filtration
b.	Buffering	d.	Hydrostatic pressure

 

 

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.

 

PTS:   1                    REF:   Page 105