$$10\text{Ca}^{2+} + 6\text{PO}_4$$^{3-}$$ + 2\text{OH}^- \rightarrow \text{Ca}_{10}(\text{PO}_4)_6(\text{OH})_2$$

Question 1

Which of the following best explains why spinach is not a great source of absorbable calcium, despite its high calcium content?

Accepted Answer

Spinach contains oxalates that inhibit calcium absorption.

Question 2

A patient presents with muscle spasms and tingling in the fingers. Blood tests reveal low serum calcium. Which term best describes this condition?

Accepted Answer

Hypocalcemia

Question 3

Which hormone is released by the parathyroid glands in response to low blood calcium levels, and what is its primary effect on the kidneys?

Accepted Answer

Parathyroid hormone (PTH); increases calcium reabsorption

Question 4

Which of the following is a major dietary source of phosphorus?

Accepted Answer

Animal products

Question 5

A person has been taking excessive calcium supplements for several years. Which of the following is a likely consequence?

Accepted Answer

Kidney stones

Question 6

Which mineral combines with phosphate to form hydroxyapatite, the hard component of bones and teeth?

Accepted Answer

Calcium

Question 7

Which of the following best describes the effect of calcitonin on blood calcium levels?

Accepted Answer

It decreases blood calcium by inhibiting bone resorption.

Question 8

A patient with chronic kidney disease is at risk for which mineral imbalance due to impaired excretion?

Accepted Answer

Hyperphosphatemia

Question 9

Which of the following factors would most likely decrease calcium absorption from the diet?

Accepted Answer

High intake of phytates

Question 10

If a person’s blood calcium is low, which sequence of events is most likely to occur?

Accepted Answer

Parathyroid hormone is released, stimulating bone resorption and increasing kidney reabsorption of calcium.

Question 11

Which of the following equations correctly represents the formation of hydroxyapatite in bone?

Accepted Answer

$$10	ext{Ca}^{2+} + 6	ext{PO}_4$$^{3-}$$ + 2	ext{OH}^- ightarrow 	ext{Ca}_{10}(	ext{PO}_4)_6(	ext{OH})_2$$

Question 12

Which of the following is NOT a function of phosphorus in the body?

Accepted Answer

Component of hemoglobin

Question 13

A patient with vitamin D deficiency is most likely to experience which of the following effects on calcium and phosphorus metabolism?

Accepted Answer

Decreased intestinal absorption of both calcium and phosphorus

Question 14

Which of the following best describes the relationship between calcium and phosphorus in bone health?

Accepted Answer

Both are required in a specific ratio to form hydroxyapatite crystals.

Question 15

Which of the following symptoms is most likely to be seen in someone with chronic hypocalcemia?

Accepted Answer

Muscle spasms and tetany

Question 16

Which of the following statements about calcium regulation is correct?

Accepted Answer

The thyroid gland releases calcitonin when blood calcium is high.

Question 17

A diet very high in phosphorus but low in calcium is most likely to result in which of the following?

Accepted Answer

Decreased bone mineralization

Question 18

Which of the following is a common effect of excessive phosphorus intake?

Accepted Answer

Calcification of soft tissues

Question 19

Which of the following best describes the main dietary concern for calcium in the United States?

Accepted Answer

Many females consume less than the recommended intake.

Question 20

Which of the following best explains why kidney disease can lead to hypocalcemia?

Accepted Answer

Impaired activation of vitamin D reduces calcium absorption.

Major Minerals: Calcium and Phosphorus – Functions, Regulation, and Dietary Sources

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