Question 1

Which of the following best describes the organizational structure of an osteon in compact bone?

Accepted Answer

A central canal surrounded by concentric lamellae, with osteocytes housed in lacunae connected by canaliculi.

Question 2

During hypocalcemia, which gland is primarily responsible for initiating the negative feedback response to restore blood calcium levels?

Accepted Answer

Parathyroid gland

Question 3

Which hormone is released during hypercalcemia to decrease blood calcium levels, and what is its primary target?

Accepted Answer

Calcitonin; inhibits osteoclast activity in bone

Question 4

Appositional bone growth differs from interstitial bone growth in that:

Accepted Answer

Appositional growth increases bone diameter by adding new layers to the surface, while interstitial growth increases bone length by expanding cartilage within the epiphyseal plate.

Question 5

Which of the following correctly lists the four steps of fracture repair in order?

Accepted Answer

Hematoma formation, fibrocartilaginous (soft) callus formation, bony (hard) callus formation, bone remodeling

Question 6

If a patient has low blood calcium ($$Ca^{2+}) $$levels, which of the following physiological responses is most likely to occur?

Accepted Answer

Increased secretion of parathyroid hormone, leading to increased osteoclast activity and release of $$Ca^{2+}$$ from bone

Question 7

Which cell type is primarily responsible for bone resorption during the negative feedback response to hypocalcemia?

Accepted Answer

Osteoclasts

Question 8

A patient with a thyroid tumor secreting excess calcitonin would most likely experience which of the following effects?

Accepted Answer

Decreased blood calcium levels due to inhibition of osteoclasts

Question 9

Which tissue type composes the soft callus during the second stage of fracture repair?

Accepted Answer

Fibrocartilage

Question 10

During bone remodeling after a fracture, which process is primarily responsible for restoring the bone's original shape and structure?

Accepted Answer

Coordinated activity of osteoclasts and osteoblasts

Question 11

Which of the following equations best represents the relationship between bone resorption and blood calcium levels?

Accepted Answer

$$\Delta [Ca$$^{2+}$$]_{blood} = R_{bone} - D_{bone}$$

Question 12

Which of the following scenarios best illustrates a negative feedback loop in calcium homeostasis?

Accepted Answer

Low blood calcium stimulates parathyroid hormone release, which increases blood calcium, then inhibits further hormone release.

Question 13

Which of the following is NOT a component of the osteon structure?

Accepted Answer

Trabeculae

Question 14

A child is experiencing stunted growth due to a defect in the epiphyseal plate. Which type of bone growth is most directly affected?

Accepted Answer

Interstitial growth

Question 15

Which cell type is most active during the formation of the hard (bony) callus in fracture repair?

Accepted Answer

Osteoblasts

Question 16

Which of the following best explains why bone remodeling is necessary after fracture repair?

Accepted Answer

To restore the bone's original shape and strength by replacing excess callus with compact bone

Question 17

Which of the following best describes the role of canaliculi in an osteon?

Accepted Answer

They allow communication and nutrient exchange between osteocytes.

Question 18

A patient with chronic kidney disease is unable to reabsorb calcium efficiently. Which hormone's effect is most compromised in this scenario?

Accepted Answer

Parathyroid hormone

Question 19

Which of the following is a direct effect of parathyroid hormone ($$PTH) on $$bone tissue?

Accepted Answer

$$PTH$$ stimulates osteoclasts to increase bone resorption and release $$Ca^{2+}$$ into the blood.

Bone Structure, Feedback Mechanisms, and Fracture Repair: Study Notes for Anatomy & Physiology

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