Practice Questions & Answers
Exam Overview:
NSG 3850 Exam 1 focuses on fluid and electrolyte homeostasis, acid-base balance, and
foundational pathophysiology concepts. It covers body fluid compartments, hormonal
regulation (ADH, aldosterone, ANP/BNP), fluid imbalances (hypovolemia/hypervolemia),
electrolyte imbalances (sodium, potassium, calcium, magnesium, phosphate), and acid-
base disorders. The exam emphasizes clinical manifestations, pathophysiology, and
assessment skills .
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EXAM SCOPE
Topic Key Areas
Fluid & Electrolyte ICF vs ECF composition, hormonal regulation, fluid
Homeostasis distribution, aging effects
Fluid Imbalances Hypovolemia (volume deficit), Hypervolemia (volume
excess)
Electrolyte Imbalances Sodium, Potassium, Calcium, Magnesium, Phosphate
Acid-Base Balance Metabolic acidosis/alkalosis, Respiratory
acidosis/alkalosis, Compensation mechanisms
FLUID & ELECTROLYTE HOMEOSTASIS
Q1. A patient is admitted with confusion, muscle weakness, and a serum sodium
level of 125 mEq/L. Which imbalance is most likely?
Answer: Hyponatremia
Rationale: Serum sodium of 125 mEq/L is below normal (135–145 mEq/L). Neurologic
symptoms (confusion, lethargy, seizures) are hallmark signs of hyponatremia due to
cerebral edema as water shifts into brain cells .
, Q2. What is the most sensitive indicator of a gain or loss of body fluid?
Answer: Daily weight measurements
Rationale: Daily weight is the most reliable indicator of fluid status. A change of 1 kilogram
(2.2 lbs) is equivalent to 1 liter of fluid gained or lost .
Q3. In adults, what fraction of total body water is contained in the intracellular space?
Answer: Two thirds
Rationale: Approximately two thirds (about 66%) of total body water is contained in the
intracellular fluid compartment; the remaining one third is in the extracellular compartment .
Q4. Which electrolytes are high in intracellular fluid (ICF)?
Answer: Potassium, magnesium, proteins, and phosphates
Rationale: ICF is rich in potassium, magnesium, proteins, and inorganic phosphates; it is
low in sodium and chloride. ECF is rich in sodium, chloride, and bicarbonate .
Q5. Which hormones regulate fluid balance?
Answer: ADH, Aldosterone, ANP/BNP
Rationale: ADH promotes water reabsorption; Aldosterone promotes sodium and water
retention; ANP/BNP promote fluid excretion. Renal prostaglandins and sympathetic nerves
also play roles .
Q6. How does aging affect fluid balance?
Answer: Decreased total body water, decreased thirst sensation, decreased GFR,
increased risk of dehydration
Rationale: Older adults have ↓ total body water, ↓ thirst sensation, ↓ GFR, and ↑ risk of
dehydration .
FLUID IMBALANCES