CVS Practice Test

The extracellular concentration of sodium in the human body is typically within the range of 135 to 145 mmol/L. Sodium is a vital electrolyte that plays a key role in maintaining fluid balance, nerve function, and muscle contraction.

This concentration is critical for various physiological processes, including the regulation of blood pressure and the functioning of cells. Values outside this range can indicate potential health issues; for instance, concentrations below 135 mmol/L can suggest hyponatremia, while values above 145 mmol/L may indicate hypernatremia, both of which can lead to severe bodily dysfunctions.

The other ranges provided do not pertain to normal sodium concentrations in extracellular fluid. For example, the range of 3.5-5.5 mmol/L typically refers to potassium levels in the blood, while the 95-110 mmol/L range is more aligned with certain pathophysiological states or conditions rather than the normal sodium levels necessary for proper physiological function.