Question 1

Which of the following best describes the role of osteoclasts in bone remodeling?

Accepted Answer

They resorb bone by secreting lysosomal enzymes and protons (H+), digesting the matrix.

Question 2

A patient presents with muscle spasms and tingling sensations. Blood tests reveal a calcium level of 7 mg/dl. Which condition is most likely, and what is the physiological explanation?

Accepted Answer

Hypocalcemia; low calcium levels cause hyperexcitability of nerves and muscles.

Question 3

Which hormone is primarily responsible for increasing blood calcium levels, and what is its mechanism of action?

Accepted Answer

Parathyroid hormone (PTH); stimulates osteoclasts to resorb bone, releasing calcium into the blood.

Question 4

According to Wolff’s law, which of the following scenarios would most likely result in increased bone density in a specific region?

Accepted Answer

A weightlifter who regularly performs exercises that stress the forearm muscles.

Question 5

Which of the following best describes the sequence of events in bone fracture repair?

Accepted Answer

Hematoma forms → Fibrocartilaginous callus forms → Bony callus forms → Bone remodeling occurs

Question 6

A 70-year-old patient suffers a hip fracture after a minor fall. Which factor most likely contributed to the fracture?

Accepted Answer

Bone thinning and decreased bone strength associated with aging.

Question 7

Which of the following is a direct effect of mechanical stress on bone tissue?

Accepted Answer

It produces electrical signals that stimulate bone remodeling.

Question 8

A patient has sustained a compound fracture. Which of the following best describes this injury?

Accepted Answer

The bone is broken and the skin is penetrated.

Question 9

Which of the following is a function of osteocytes in bone tissue?

Accepted Answer

They maintain the bone matrix and act as mechanosensors.

Question 10

Which of the following best explains why the diaphysis of long bones is thickest where bending stresses are greatest?

Accepted Answer

Because compression and tension forces are greatest at the diaphysis, stimulating bone remodeling.

Question 11

Which of the following is a plausible trigger for bone deposition by osteoblasts?

Accepted Answer

Mechanical signals and increased concentrations of calcium and phosphate ions.

Question 12

A patient with sustained high blood calcium levels is at risk for which of the following complications?

Accepted Answer

Formation of kidney stones due to calcium salt deposits.

Question 13

Which of the following best describes the role of parathyroid hormone (PTH) in bone remodeling?

Accepted Answer

PTH stimulates osteoclasts to resorb bone, increasing blood calcium levels.

Question 14

Which of the following is the correct formula for the normal range of blood calcium concentration?

Accepted Answer

$9-11\ \mathrm{mg/dl}$

Question 15

During the bone repair process, what is the primary function of the fibrocartilaginous callus?

Accepted Answer

To connect broken bone ends and provide a framework for new bone formation.

Question 16

Which of the following best explains why bones of bedridden patients become featureless?

Accepted Answer

Lack of mechanical stress leads to decreased bone remodeling and loss of bone features.

Question 17

Which of the following is NOT a typical step in the repair of a bone fracture?

Accepted Answer

Immediate restoration of compact bone without callus formation.

Question 18

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

Accepted Answer

It has negligible effects at normal levels but can lower blood calcium temporarily at high doses.

Question 19

Which of the following best describes the difference between open (compound) and closed (simple) fractures?

Accepted Answer

Open fractures penetrate the skin, while closed fractures do not.

Bone Remodeling and Repair: Structure, Regulation, and Healing

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