What does it mean when we say that the concentration of Ca²⁺ in blood is 3.0 mEq/L?

Verified step by step guidance

1. Understand that 'mEq/L' stands for milliequivalents per liter, a unit used to express the concentration of ions in a solution.
2. Recognize that the term 'equivalent' relates to the amount of charge that an ion contributes to a solution.
3. Recall that calcium ions (Ca²⁺) have a charge of +2, meaning each ion contributes two equivalents of charge.
4. Calculate the milliequivalents by considering the charge: 1 mEq of Ca²⁺ corresponds to 0.5 mmol of Ca²⁺ because each Ca²⁺ ion has a charge of +2.
5. Interpret the given concentration: 3.0 mEq/L of Ca²⁺ means there are 3.0 milliequivalents of calcium ions per liter of blood, which corresponds to 1.5 mmol/L of Ca²⁺.

Key Concepts

Concentration Units

Concentration is a measure of the amount of a substance in a given volume of solution. In this case, 'mEq/L' stands for milliequivalents per liter, which is a unit used to express the concentration of ions in a solution, taking into account both the charge of the ion and its molar mass.

Milliequivalents

A milliequivalent (mEq) is a unit that quantifies the reactive capacity of an ion. It is calculated based on the ion's valence (charge) and its molar concentration. For calcium ions (Ca²⁺), which have a valence of +2, 1 mEq of Ca²⁺ corresponds to 0.5 mmol, making it essential for understanding electrolyte balance in the body.

Physiological Significance of Ca²⁺

Calcium ions (Ca²⁺) play a critical role in various physiological processes, including muscle contraction, blood clotting, and neurotransmitter release. The concentration of Ca²⁺ in blood is tightly regulated, as deviations can lead to significant health issues, highlighting the importance of understanding its measurement in mEq/L.