A patient has a serum sodium level of 165 mEq/L. The healthcare professional explains that the
clinical manifestations of confusion, convulsions,
... [Show More] cerebral hemorrhage, and coma are caused by
what mechanism?
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. Low sodium in the blood vessels pulls potassium out of the brain cells,
which slows the synapses in the brain.
d. Low sodium in the blood vessels draws chloride into the brain cells followed by
water, causing the brain cells to swell.
ANS: A
A normal serum sodium level is 135 to 145 mEq/L so this patient’s level is high. Hypernatremia
causes manifestations by pulling water out of the brain cells into the blood vessels.
PTS: 1 DIF: Cognitive Level: Applying
16. What does vomiting-induced metabolic alkalosis cause?
a. Retained sodium to bind with the chloride
b. Hydrogen to move into the cell and exchange with potassium
c. Retention of bicarbonate to maintain the anion balance
d. Hypoventilation to compensate for the metabolic alkalosis
ANS: C
When vomiting with the depletion of ECF and chloride (hypochloremic metabolic alkalosis)
causes acid loss, renal compensation is not effective; the volume depletion and loss of
electrolytes (sodium [Na+], potassium [K+], hydrogen [H+], chlorine [Cl–]) stimulate a paradoxic
response by the kidneys. The kidneys increase sodium and bicarbonate reabsorption with the
excretion of hydrogen. Bicarbonate is reabsorbed to maintain an anionic balance because the
ECF chloride concentration is decreased. Metabolic alkalosis will not lead to retained sodium,
hydrogen movement into the cell, or hypoventilation.
PTS: 1 DIF: Cognitive Level: Remembering
17. The pathophysiologic process of edema is related to which mechanism?
a. Sodium depletion
b. Decreased capillary hydrostatic pressure
c. Increased plasma oncotic pressure
d. Lymphatic obstruction
ANS: D
The pathophysiologic process of edema is related to an increase in the forces favoring fluid
filtration from the capillaries or lymphatic channels into the tissues. The most common
mechanisms are increased capillary hydrostatic pressure, decreased plasma oncotic pressure,
increased capillary membrane permeability and lymphatic obstruction, and sodium retention.
PTS: 1 DIF: Cognitive Level: Remembering
18. Why is insulin used to treat hyperkalemia?
a. Stimulates sodium to be removed from the cell in exchange for potassium
b. Binds to potassium to remove it through the kidneys
c. Transports potassium from the blood into the cell along with glucose
d. Breaks down the chemical components of potassium, inactivating it
ANS: C
Insulin promotes the uptake of K+ by stimulating the Na+-K+-ATPase pump. It does not stimulate
the removal of sodium from the cell nor does it bind to K+ to excrete it. The Na+-K+-ATPase
pump does facilitate movement of K+ into liver and muscle cells along with glucose to regulate
blood glucose after eating.
PTS: 1 DIF: Cognitive Level: Remembering
19. A major determinant of the resting membrane potential necessary for the transmission of nerve
impulses is the ratio between what?
a. Intracellular and extracellular Na+
b. Intracellular and extracellular K+
c. Intracellular Na+ 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.
PTS: 1 DIF: Cognitive Level: Remembering
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
b. Sodium
c. Potassium
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.
PTS: 1 DIF: Cognitive Level: Remembering
21. A healthcare professional is caring for four patients. Which patient should the professional
assess for hyperkalemia?
a. Hyperparathyroidism
b. Vomiting
c. Renal failure
d. Hyperaldosteronism
ANS: C
Hyperkalemia should be investigated when a history of renal disease, massive trauma, insulin
deficiency, Addison disease, use of potassium salt substitutes, or metabolic acidosis exists.
Hyperparathyroidism might lead to hyperphosphatemia. Vomiting is frequently associated with
potassium depletion. Hyperaldosteronism also can lead to potassium wasting.
PTS: 1 DIF: Cognitive Level: Applying
22. In hyperkalemia, what change occurs to the cells’ resting membrane potential?
a. Hypopolarization
b. Hyperexcitability
c. Depolarization
d. Repolarization
ANS: A
In hyperkalemia, the cells’ 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).
PTS: 1 DIF: Cognitive Level: Knowledge
23. A patient’s chart indicates Kussmaul respirations. The student asks the healthcare professional
what this is caused by. What response by the professional is most accurate?
a. Anxiety leads to Kussmaul respirations and is a cause of respiratory acidosis.
b. A compensatory measure is needed to correct metabolic acidosis.
c. Diabetic ketoacidosis is leading to metabolic acidosis.
d. More oxygen is necessary to compensate for respiratory acidosis.
ANS: B
Deep, rapid respirations (Kussmaul respirations) are indicative of respiratory compensation for
metabolic acidosis. Anxiety would lead to respiratory alkalosis as carbon dioxide is blown off by
the lungs. Kussmaul’s respirations may be seen in diabetic ketoacidosis, but they do not diagnose
it. Kussmaul’s respirations are not present in respiratory acidosis.
PTS: 1 DIF: Cognitive Level: Comprehension
24. A healthcare provider notes that tapping the patient’s facial nerve leads to lip twitching. What
electrolyte value is correlated with this finding?
a. K+: 2.8 mEq/L
b. K+: 5.4 mEq/L
c. Ca++: 8.2 mg/dL
d. Ca++: 12.9 mg/dL
ANS: C
This patient has a positive Chvostek sign, which is indicative of hypocalcemia. The normal range
of Ca++ is 9 to 10.5 mg/dL. 12.9 mg/dL indicates hypercalcemia. Potassium imbalances are not
related.
PTS: 1 DIF: Cognitive Level: Analyzing
25. A patient has a history of excessive use of magnesium-containing antacids and aluminumcontaining
antacids. What lab value does the healthcare professional correlate to this
behavior?
a. Magnesium 1.8 mg/dL
b. Phosphate 1.9 mg/dL
c. Sodium 149 mEq/L
d. Potassium 2.5 mEq/L
ANS: B
Excessive use of magnesium-containing and aluminum-containing antacids can lead to
hypophosphatemia, which is a serum level less than 2 mg/dL. The magnesium level is normal,
but magnesium is not related. The sodium level is high, but that is not related. The potassium
level is low, but this is also not related.
PTS: 1 DIF: Cognitive Level: Analyzing
26. A healthcare professional is caring for four patients. Which patient should the professional
assess for hypermagnesemia as [Show Less]