Pathophysiology The Biologic Basis For Disease in Adults and Children 7th Edition Mccance Test Bank
Pathophysiology The Biologic Basis For Disease in Adults and Children 7th Edition Mccance Test Bank
Pathophysiology The Biologic Basis For Disease in Adults and Children 7th Edition Mccance Test Bank
Chapter 3: The Cellular Environment: Fluids and Electrolytes, Acids and Bases
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.
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.
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
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.
7. At the arterial end of capillaries, fluid moves from the intravascular space into the interstitial
space because the:
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: 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.
9. Secretion of antidiuretic hormone (ADH) and the perception of thirst are stimulated by a(n):
a. Decrease in serum sodium c. Increase in glomerular filtration rate
b. Increase in plasma osmolality d. Decrease in osmoreceptor stimulation
ANS: B
Secretion of ADH and the perception of thirst are primary factors in the regulation of water
balance. Thirst is a sensation that stimulates water-drinking behavior. Thirst is experienced
when water loss equals 2% of an individual’s body weight or when osmotic pressure
increases. The other options do not accurately describe how ADH and the perception of thirst
are related.
12. When changes in total body water are accompanied by proportional changes in electrolytes,
what type of alteration occurs?
a. Isotonic c. Hypotonic
b. Hypertonic d. Normotonic
ANS: A
Only isotonic alterations occur when proportional changes in electrolytes and water
accompany changes in total body water .
PTS: 1 REF: Pages 109-110
13. Which enzyme is secreted by the juxtaglomerular cells of the kidney when circulating blood
volume is reduced?
a. Angiotensin I c. Aldosterone
b. Angiotensin II d. Renin
ANS: D
When circulating blood volume or blood pressure is reduced, renin, an enzyme secreted by
the juxtaglomerular cells of the kidney, is released in response to sympathetic nerve
stimulation and decreased perfusion of the renal vasculature. The other options are not
released by the situation described in the question.
15. What causes the clinical manifestations of confusion, convulsions, cerebral hemorrhage, and
coma in hypernatremia?
a. High sodium in the blood vessels pulls water out of the brain cells into the blood
vessels, causing brain cells to shrink.
b. High sodium in the brain cells pulls water out of the blood vessels into the brain
cells, causing them to swell.
c. High sodium in the blood vessels pulls potassium out of the brain cells, which
slows the synapses in the brain.
d. High sodium in the blood vessels draws chloride into the brain cells followed by
water, causing the brain cells to swell.
ANS: A
Hypertonic (hyperosmolar) imbalances result in an extracellular fluid concentration greater
than 0.9% salt solution (e.g., water loss or solute gain); cells shrink in a hypertonic fluid (see
Table 3-7). This shrinking of cells results in the symptoms described in the question. The
other options do not accurately describe the cause of these symptoms as they relate to
hypernatremia.
19. A major determinant of the resting membrane potential necessary for the transmission of
nerve impulses is the ratio between:
a. Intracellular and extracellular Na+ c. Intracellular Na+ and extracellular K+
b. Intracellular and extracellular K+ d. Intracellular K+ and extracellular Na+
ANS: B
The ratio of K+ in the ICF to K+ in the ECF is the major determinant of the resting membrane
potential, which is necessary for the transmission and conduction of nerve impulses, for the
maintenance of normal cardiac rhythms, and for the skeletal and smooth muscle contraction.
This is not true of the other options.
20. During acidosis, the body compensates for the increase in serum hydrogen ions by shifting
hydrogen ions into the cell in exchange for which electrolyte?
a. Oxygen c. Potassium
b. Sodium d. Magnesium
ANS: C
In states of acidosis, hydrogen ions shift into the cells in exchange for intracellular fluid
potassium; hyperkalemia and acidosis therefore often occur together. This is not true of the
other options.
22. In hyperkalemia, what change occurs to the cells’ resting membrane potential?
a. Hypopolarization c. Depolarization
b. Hyperexcitability d. Repolarization
ANS: A
If extracellular potassium concentration increases without a significant change in intracellular
potassium, then the resting membrane potential becomes more positive (i.e., changes from
–90 to –80 mV) and the cell membrane is hypopolarized (i.e., the inside of the cell becomes
less negative or partially depolarized [increase excitability]).
23. The calcium and phosphate balance is influenced by which three substances?
a. Parathyroid hormone, vasopressin, and vitamin D
b. Parathyroid hormone, calcitonin, and vitamin D
c. Thyroid hormone, vasopressin, and vitamin A
d. Thyroid hormone, calcitonin, and vitamin A
ANS: B
Three hormones regulate calcium and phosphate balance: parathyroid hormone (PTH),
vitamin D, and calcitonin. Vasopressin, thyroid hormone, and vitamin A do not influence
calcium and phosphate balance.
28. Physiologic pH is maintained at approximately 7.4 because bicarbonate (HCO3) and carbonic
acid (H2CO3) exist in a ratio of:
a. 20:1 c. 10:2
b. 1:20 d. 10:5
ANS: A
The relationship between HCO3 and H2CO3 is usually expressed as a ratio. When the pH is
7.4, this ratio is 20:1 (HCO3:H2CO3). The other options do not accurately identify physiologic
pH by the correct ratio of HCO3 and H2CO3.
29. Which arterial pH will initiate the formation of ammonium (NH4) from ammonia (NH3),
referred to as academia, in the tubular lumen of the kidney?
a. 7.25 c. 7.55
b. 7.35 d. 7.65
ANS: A
Pathophysiologic changes in the concentration of hydrogen ion or base in the blood lead to
acid-base imbalances. Acidemia is a state in which the pH of arterial blood is less than 7.35.
NH3 is produced from glutamine in the epithelial cell and diffuses to the tubular lumen, where
it combines with H+ to form NH4.
MULTIPLE RESPONSE
34. Which groups are at risk for fluid imbalance? (Select all that apply.)
a. Women
b. Infants
c. Men
d. Obese persons
e. Older adults
ANS: B, D, E
Kidney function, surface area, total body water, and the hydrophobic nature of fat cells all
contribute to the increased risk for fluid imbalance among obese individuals, infants, and
older adults. Gender alone is not a risk factor for fluid imbalance.
35. Dehydration can cause which result? (Select all that apply.)
a. Moist mucous membranes
b. Weak pulses
c. Tachycardia
d. Polyuria
e. Weight loss
ANS: B, C, E
Significant water deficit is demonstrated by symptoms of dehydration that include headache,
thirst, dry skin and mucous membranes, elevated temperature, weight loss, and decreased or
concentrated urine (with the exception of diabetes insipidus). Skin turgor may be normal or
decreased. Symptoms of hypovolemia include tachycardia, weak pulses, and postural
hypotension.
37. The electrolyte imbalance called hyponatremia exhibits which clinical manifestations? (Select
all that apply.)
a. Headache
b. Seizures
c. Paranoia
d. Confusion
e. Lethargy
ANS: A, B, D, E
Behavioral and neurologic changes characteristic of hyponatremia include lethargy, headache,
confusion, apprehension, seizures, and coma. Paranoia is not associated with hyponatremia.
38. The electrolyte imbalance hypercalcemia exhibits which clinical manifestations? (Select all
that apply.)
a. Diarrhea
b. Calcium based kidney stones
c. ECG showing narrow T waves
d. Lethargy
e. Bradycardia
ANS: B, D, E
Fatigue, weakness, lethargy, anorexia, nausea, and constipation are common. Behavioral
changes may occur. Impaired renal function frequently develops, and kidney stones form as
precipitates of calcium salts. A shortened QT segment and depressed widened T waves also
may be observed on the ECG, with bradycardia and varying degrees of heart block.
PTS: 1 REF: Pages 120-121
39. The electrolyte imbalance hypokalemia exhibits which clinical manifestations? (Select all that
apply.)
a. Paralytic ileus
b. Sinus bradycardia
c. Atrioventricular block
d. Dry mucous membranes
e. Tetany
ANS: A, B, C
A variety of dysrhythmias may occur, including sinus bradycardia, atrioventricular block,
paroxysmal atrial tachycardia, and paralytic ileus. The other options are not related to
hypokalemia.
40. A third of the body’s fluid is contained in the extracellular interstitial fluid spaces that include:
(Select all that apply.)
a. Urine
b. Intraocular fluids
c. Lymph
d. Blood plasma
e. Sweat
ANS: A, B, C, E
Two thirds of the body’s water is in the intracelluarl fluid (ICF) compartment, and one third is
in the extracellular fluid (ECF) compartments. The two main ECF compartments are the
interstitial fluid and the intravascular fluid, such as the blood plasma. Interstitial ECF
compartments include the lymph and the transcellular fluids, such as the synovial, intestinal,
biliary, hepatic, pancreatic, and cerebrospinal fluids; sweat; urine; and pleural, synovial,
peritoneal, pericardial, and intraocular fluids.
41. An imbalance of potassium can produce which dysfunctions? (Select all that apply.)
a. Weakness skeletal muscles
b. Cardiac dysrhythmias
c. Smooth muscle atony
d. Visual impairment
e. Hearing loss
ANS: A, B, C
Symptoms of hyperkalemia vary, but common characteristics are muscle weakness or
paralysis and dysrhythmias with changes in the ECG. A wide range of metabolic dysfunctions
may result from hypokalemia. Neuromuscular excitability is decreased, causing skeletal
muscle weakness, smooth muscle atony, and cardiac dysrhythmias.
42. Which statements regarding total body water (TBW) are true? (Select all that apply.)
Pathophysiology The Biologic Basis for Disease in Adults and Children 7th Edition Mccance Te
MATCHING
Match the electrolytes with the corresponding descriptions. Terms may be used more than
once.
______ A. Sodium
______ B. Chloride
______ C. Potassium
______ D. Magnesium
______ E. Phosphate
43. Regulates osmolality in the extracellular fluid (ECF) space.
44. Is inversely related to HCO3 concentration.
45. Is a major determinant of resting membrane potential.
46. An intracellular metabolic form is adenosine triphosphate (ATP).
47. Changes in hydrogen ion concentration affect this electrolyte.