Which of the following are the most abundant minerals in the human body?

Appeared in: UPRVUNL - 2021

Explanation

Calcium is the most abundant mineral in the body, with a total content of about 1 to 1.5 kg in an adult.
It constitutes approximately 1.5-2% of the total body weight.
About 99% of the body's calcium is located in the bones and teeth, providing structural support.
The remaining 1% is found in blood and soft tissues, playing a vital role in physiological processes like muscle contraction, nerve transmission, and blood coagulation.

Option A: Sodium is a crucial electrolyte and the primary cation in extracellular fluid, but its total body content (around 63 g) is significantly lower than that of calcium.
Option B: Potassium is the most abundant intracellular cation and is vital for nerve and muscle function, but its total amount in the body (around 150 g) is much less than calcium.
Option D: Iron is classified as a trace mineral because the body requires it in very small amounts. The total iron content in an adult is only about 3-4 grams, which is minuscule compared to calcium.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Abundance of minerals in the human body as background academic context rather than a clinical decision trigger.
Nurses must monitor serum calcium levels (normal: 8.5-10.5 mg/dL) in patients with thyroid/parathyroid disorders, kidney disease, or certain cancers, as imbalances can be life-threatening.
Assessing for signs of hypocalcemia (Trousseau's and Chvostek's signs) and hypercalcemia (muscle weakness, confusion, cardiac arrhythmias) is a critical nursing responsibility.
Patient education on dietary sources of calcium (e.g., dairy products, leafy greens) is important for preventing osteoporosis and maintaining bone health.

How to Approach the Question

First, identify the core question: it asks for the 'most abundant' mineral in the body.
Recall the classification of minerals into macro-minerals (required in amounts greater than 100 mg/day) and trace minerals (required in smaller amounts).
Recognize that Sodium, Potassium, and Calcium are macro-minerals, while Iron is a trace mineral. This makes Iron an unlikely answer.
Compare the relative abundance of the macro-minerals. Remember that the vast majority of the body's mineral content is stored as calcium phosphate in the skeleton.
Conclude that Calcium, being the primary component of bones and teeth, is present in the largest quantity (kilograms) compared to Sodium and Potassium (grams).

Concept Tested & Keywords

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E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) pp. 21-23, 22-24

E6 textbook of Applied Biochemistry and Nutrition & DieteticsHarbans Lal (pp 26-464 of 479) p. 296-298

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