Paramedic National Registry Practice

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Prepare for the Paramedic National Registry Exam with comprehensive quizzes and study materials. Gain confidence with multiple choice questions, hints, and detailed explanations to excel in your exam.

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Which ion is the most abundant in the human body?

Sodium
Calcium
Potassium
Magnesium

The correct answer is: Calcium

The most abundant ion in the human body is calcium. Calcium plays several vital roles in biological processes, including muscle contraction, blood clotting, and neurotransmitter release. Approximately 99% of the body's calcium is stored in bones and teeth, where it provides structural support and rigidity. The remaining calcium is found in the blood and soft tissues, where it is crucial for physiological functions. In the context of other ions, while sodium and potassium are essential for maintaining cellular function and fluid balance, they are present in lower quantities compared to calcium, particularly in mineralized tissues. Magnesium, although important for numerous biochemical reactions, is also less abundant than calcium in the context of overall body composition. Thus, calcium's predominance in bones and its critical roles in various body systems contribute to its status as the most abundant ion in the human body.