sodium

(sōd′ē-ŭm)

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[soda + -ium (1)]
SYMB: Na An inorganic metallic element, atomic weight (mass) 22.98987, atomic number 11, specific gravity 0.971. Sodium constitutes about 0.15% of body mass. It is the most abundant cation in extracellular fluids, the main contributor to osmotic pressure and hydration, participates in many specialized pumps and receptors on cell membranes, and plays a fundamental part in the electrical activities of the body, e.g., nerve impulse transmission and muscular contraction.
CAS # 7440-23-5

The normal sodium level in serum is 135 to 145 mmol/L. A decreased level of sodium in the serum is called hyponatremia, an increased level, hypernatremia.
SYN: SEE: natrium
SEE: hypernatremia; SEE: hyponatremia

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