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

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

Question 1

Which of the following best describes the role of collagen in bone structure?

Accepted Answer

Collagen is responsible for the flexibility and strength of bone due to its triple helix fibrous structure.

Question 2

A 16-year-old female athlete has not yet started menstruation and has a low body weight. Which of the following is she at greatest risk for regarding her bone health?

Accepted Answer

Achieving a lower peak bone density, increasing her risk for osteoporosis later in life

Question 3

Which process is primarily responsible for maintaining calcium homeostasis in the body?

Accepted Answer

Bone remodeling

Question 4

What is the main function of osteoclasts during bone remodeling?

Accepted Answer

Eroding bone surfaces to release calcium and phosphorus into the bloodstream

Question 5

Which hormone is released when blood calcium levels fall below normal, and what is its effect?

Accepted Answer

Parathyroid hormone (PTH); stimulates osteoclasts to release calcium from bone

Question 6

A patient consumes a diet very high in phytates and oxalates. What is the most likely effect on their calcium status?

Accepted Answer

Decreased calcium absorption due to inhibition by phytates and oxalates

Question 7

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 8

Which of the following statements about calcium absorption is TRUE?

Accepted Answer

Vitamin D is essential for optimal calcium absorption in the small intestine.

Question 9

A 55-year-old woman is concerned about osteoporosis. Which combination of nutrients is most critical for her bone health?

Accepted Answer

Calcium, phosphorus, vitamin D, and vitamin K

Question 10

Which of the following foods is the richest natural source of vitamin D?

Accepted Answer

Fatty fish such as salmon or sardines

Question 11

A patient presents with muscle spasms, abnormal heart rhythms, and low blood calcium. Which condition is most likely?

Accepted Answer

Hypocalcemia

Question 12

Which of the following is a function of magnesium in the body?

Accepted Answer

It is a cofactor for over 300 enzyme systems, including those involved in ATP production.

Question 13

Which of the following statements about vitamin K is correct?

Accepted Answer

Vitamin K is produced by bacteria in the large intestine and is essential for bone protein synthesis.

Question 14

Which of the following scenarios would most likely result in decreased synthesis of vitamin D in the skin?

Accepted Answer

An older adult with dark skin living at a high latitude during winter

Question 15

Which of the following best explains why postmenopausal women are at increased risk for osteoporosis?

Accepted Answer

Decreased estrogen levels lead to increased bone resorption by osteoclasts.

Question 16

A patient is taking a calcium supplement of 1200 mg at once. What is the most likely outcome regarding absorption?

Accepted Answer

Only about 500 mg will be absorbed at one time due to saturation of transport proteins.

Question 17

Which of the following is a major function of phosphorus in the body?

Accepted Answer

It is a component of ATP, DNA, and RNA.

Question 18

Which of the following dietary patterns would most likely increase urinary calcium excretion?

Accepted Answer

A diet high in salt and protein

Question 19

Which of the following best describes the relationship between dietary calcium intake and calcium absorption?

Accepted Answer

Calcium absorption is negatively proportional to dietary intake; higher intake leads to lower absorption.

Question 20

A vegan patient is concerned about getting enough calcium. Which of the following foods would you recommend as a good plant-based source?

Accepted Answer

Tofu

Nutrients Essential for Bone Health: Structure, Function, and Dietary Sources

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