VPY-0100
QUESTION
Sodium pump decreases the concentration of sodium ions inside the nerve fiber to?
OPTIONS
(A) 5 m Eq/1
(B) 10 m Eq/1
(C) 142 m Eq/1
(D) 150 m Eq/1
ANSWER
(B) 10 m Eq/1
EXPLANATION
10 m Eq/1 is the correct option because the sodium-potassium pump continuously extrudes Na+ from the nerve fiber, maintaining a much lower intracellular sodium concentration than the extracellular concentration; the value specified by the keyed question is approximately 10 mEq/L inside. 5 mEq/L is too low, whereas 142 and 150 mEq/L approximate extracellular rather than intracellular sodium concentrations.