C599 TEST COMPREHENSIVE QUESTIONS
AND COMPLETE SOLUTIONS
◉ In a healthy animal, what proportion of total body water is
contained within the intracellular fluid (ICF) compartment? A. One-
third B. Two-thirds C. One-half D. Three-fourths.
Answer: B. Two-thirds
◉ Which fluid sub-compartment contains approximately 15% of
total body weight? A. Intravascular fluid B. Transcellular fluid C.
Interstitial fluid D. Intracellular fluid.
Answer: C. Interstitial fluid
◉ Adipose tissue affects total body water calculations because fat
contains: A. Significantly more water than lean tissue B. Significantly
less water than lean tissue C. Equal amounts of water as lean tissue
D. No intracellular fluid space.
Answer: B. Significantly less water than lean tissue
◉ Passive movement of solute molecules down a concentration
gradient from higher to lower concentration is defined as: A.
Osmosis B. Active transport C. Diffusion D. Facilitated transport.
Answer: C. Diffusion
,◉ Passive movement of water across a semipermeable membrane
toward higher solute concentrations is called: A. Diffusion B.
Filtration C. Osmosis D. Hydrostatic displacement.
Answer: C. Osmosis
◉ Which hormone serves as the primary physiologic regulator of
plasma osmolality? A. Aldosterone B. Antidiuretic Hormone (ADH) C.
Cortisol D. Parathyroid Hormone.
Answer: B. Antidiuretic Hormone (ADH)
◉ The primary active transport pump maintaining cell volume and
resting membrane potential requires cellular ATP to move: A. 2 Na+
out for 3 K+ in B. 3 Na+ out for 2 K+ in C. 3 Na+ in for 2 K+ out D. 2
Na+ in for 3 K+ out.
Answer: B. 3 Na+ out for 2 K+ in
◉ Which of the following is the predominant extracellular cation in
dogs and cats? A. Potassium (K+) B. Magnesium (Mg2+) C. Sodium
(Na+) D. Calcium (Ca2+).
Answer: C. Sodium (Na+)
◉ Which anion is predominant in the extracellular fluid space? A.
Bicarbonate (HCO3-) B. Chloride (Cl-) C. Phosphate (PO4 3-) D.
Sulfate (SO4 2-).
Answer: B. Chloride (Cl-)
,◉ Which cation is predominant inside the intracellular fluid
compartment? A. Sodium (Na+) B. Calcium (Ca2+) C. Potassium (K+)
D. Chloride (Cl-).
Answer: C. Potassium (K+)
◉ The canine normal reference range for serum sodium (Na+) is: A.
135-145 mEq/L B. 141-155 mEq/L C. 150-165 mEq/L D. 120-135
mEq/L.
Answer: B. 141-155 mEq/L
◉ Feline normal serum potassium (K+) ranges between: A. 2.5-4.5
mEq/L B. 3.5-6.1 mEq/L C. 5.5-7.5 mEq/L D. 1.5-3.0 mEq/L.
Answer: B. 3.5-6.1 mEq/L
◉ The canine reference range for serum chloride (Cl-) is: A. 80-95
mEq/L B. 95-120 mEq/L C. 115-130 mEq/L D. 130-145 mEq/L.
Answer: B. 95-120 mEq/L
◉ What percentage of total serum calcium is biologically active as
ionized calcium (iCa2+)? A. 25% B. 40% C. 55% D. 80%.
Answer: C. 55%
, ◉ What is the primary plasma protein that binds serum calcium? A.
Globulin B. Albumin C. Fibrinogen D. Transferrin.
Answer: B. Albumin
◉ Standard EDTA anticoagulant tubes must never be used for
calcium determinations because EDTA: A. Destroys protein
structures B. Chelates calcium, causing false low values C. Falsely
elevates calcium readings D. Dilutes the plasma volume.
Answer: B. Chelates calcium, causing false low values
◉ In young, rapidly growing puppies and kittens, serum inorganic
phosphorus (iPO4 3-) is expected to be: A. Significantly lower than
adult ranges B. Identical to adult ranges C. Higher than adult ranges
due to active bone growth D. Unmeasurable on standard panels.
Answer: C. Higher than adult ranges due to active bone growth
◉ Refractory hypokalemia and hypocalcemia that fail to respond to
direct supplementation are frequently caused by concurrent: A.
Hypernatremia B. Hypomagnesemia C. Hyperphosphatemia D.
Hypochloremia.
Answer: B. Hypomagnesemia
◉ What effect does severe sample hemolysis have on measured
potassium levels in species with potassium-rich red blood cells? A.
False depression (pseudohypokalemia) B. False elevation
AND COMPLETE SOLUTIONS
◉ In a healthy animal, what proportion of total body water is
contained within the intracellular fluid (ICF) compartment? A. One-
third B. Two-thirds C. One-half D. Three-fourths.
Answer: B. Two-thirds
◉ Which fluid sub-compartment contains approximately 15% of
total body weight? A. Intravascular fluid B. Transcellular fluid C.
Interstitial fluid D. Intracellular fluid.
Answer: C. Interstitial fluid
◉ Adipose tissue affects total body water calculations because fat
contains: A. Significantly more water than lean tissue B. Significantly
less water than lean tissue C. Equal amounts of water as lean tissue
D. No intracellular fluid space.
Answer: B. Significantly less water than lean tissue
◉ Passive movement of solute molecules down a concentration
gradient from higher to lower concentration is defined as: A.
Osmosis B. Active transport C. Diffusion D. Facilitated transport.
Answer: C. Diffusion
,◉ Passive movement of water across a semipermeable membrane
toward higher solute concentrations is called: A. Diffusion B.
Filtration C. Osmosis D. Hydrostatic displacement.
Answer: C. Osmosis
◉ Which hormone serves as the primary physiologic regulator of
plasma osmolality? A. Aldosterone B. Antidiuretic Hormone (ADH) C.
Cortisol D. Parathyroid Hormone.
Answer: B. Antidiuretic Hormone (ADH)
◉ The primary active transport pump maintaining cell volume and
resting membrane potential requires cellular ATP to move: A. 2 Na+
out for 3 K+ in B. 3 Na+ out for 2 K+ in C. 3 Na+ in for 2 K+ out D. 2
Na+ in for 3 K+ out.
Answer: B. 3 Na+ out for 2 K+ in
◉ Which of the following is the predominant extracellular cation in
dogs and cats? A. Potassium (K+) B. Magnesium (Mg2+) C. Sodium
(Na+) D. Calcium (Ca2+).
Answer: C. Sodium (Na+)
◉ Which anion is predominant in the extracellular fluid space? A.
Bicarbonate (HCO3-) B. Chloride (Cl-) C. Phosphate (PO4 3-) D.
Sulfate (SO4 2-).
Answer: B. Chloride (Cl-)
,◉ Which cation is predominant inside the intracellular fluid
compartment? A. Sodium (Na+) B. Calcium (Ca2+) C. Potassium (K+)
D. Chloride (Cl-).
Answer: C. Potassium (K+)
◉ The canine normal reference range for serum sodium (Na+) is: A.
135-145 mEq/L B. 141-155 mEq/L C. 150-165 mEq/L D. 120-135
mEq/L.
Answer: B. 141-155 mEq/L
◉ Feline normal serum potassium (K+) ranges between: A. 2.5-4.5
mEq/L B. 3.5-6.1 mEq/L C. 5.5-7.5 mEq/L D. 1.5-3.0 mEq/L.
Answer: B. 3.5-6.1 mEq/L
◉ The canine reference range for serum chloride (Cl-) is: A. 80-95
mEq/L B. 95-120 mEq/L C. 115-130 mEq/L D. 130-145 mEq/L.
Answer: B. 95-120 mEq/L
◉ What percentage of total serum calcium is biologically active as
ionized calcium (iCa2+)? A. 25% B. 40% C. 55% D. 80%.
Answer: C. 55%
, ◉ What is the primary plasma protein that binds serum calcium? A.
Globulin B. Albumin C. Fibrinogen D. Transferrin.
Answer: B. Albumin
◉ Standard EDTA anticoagulant tubes must never be used for
calcium determinations because EDTA: A. Destroys protein
structures B. Chelates calcium, causing false low values C. Falsely
elevates calcium readings D. Dilutes the plasma volume.
Answer: B. Chelates calcium, causing false low values
◉ In young, rapidly growing puppies and kittens, serum inorganic
phosphorus (iPO4 3-) is expected to be: A. Significantly lower than
adult ranges B. Identical to adult ranges C. Higher than adult ranges
due to active bone growth D. Unmeasurable on standard panels.
Answer: C. Higher than adult ranges due to active bone growth
◉ Refractory hypokalemia and hypocalcemia that fail to respond to
direct supplementation are frequently caused by concurrent: A.
Hypernatremia B. Hypomagnesemia C. Hyperphosphatemia D.
Hypochloremia.
Answer: B. Hypomagnesemia
◉ What effect does severe sample hemolysis have on measured
potassium levels in species with potassium-rich red blood cells? A.
False depression (pseudohypokalemia) B. False elevation
