Q: Which of the following equations correctly represents the negative feedback loop for blood calcium regulation involving PTH?

$$\text{Low blood } Ca$$^{2+}$$ \rightarrow \text{PTH release} \rightarrow \text{Osteoclast activation} \rightarrow \text{Increased blood } Ca$$^{2+}$$

Question 1

Which of the following best describes the function of osteoclasts in bone tissue?

Accepted Answer

They resorb (break down) bone matrix, releasing calcium into the blood.

Question 2

A patient presents with bowed legs and enlarged bone ends. Laboratory tests reveal low vitamin D levels. Which bone disorder is most likely present?

Accepted Answer

Rickets

Question 3

Which hormone is primarily responsible for stimulating osteoclast activity when blood calcium levels fall below normal?

Accepted Answer

Parathyroid hormone (PTH)

Question 4

During endochondral ossification, what is the first major event that occurs?

Accepted Answer

Formation of a bone collar around the diaphysis of the cartilage model

Question 5

Which of the following is a correct equation for the mineral component of bone, hydroxyapatite?

Accepted Answer

$$\mathrm{Ca_{10}(PO_4$)_6(OH)_2}$$

Question 6

A 70-year-old woman suffers a hip fracture after a minor fall. Her X-ray shows decreased bone mass, especially in the femoral neck. Which process is most likely increased in her bones?

Accepted Answer

Bone resorption by osteoclasts

Question 7

Which of the following best explains why weight-bearing exercise helps prevent osteoporosis?

Accepted Answer

It stimulates bone remodeling by increasing mechanical stress, which enhances osteoblast activity.

Question 8

Which of the following bone markings is correctly matched with its function?

Accepted Answer

Condyle – rounded articular projection

Question 9

A child’s long bone is growing in length. Which zone of the epiphyseal plate is responsible for the rapid division of cartilage cells?

Accepted Answer

Proliferation (growth) zone

Question 10

Which of the following statements about bone remodeling is correct?

Accepted Answer

It involves both bone deposition by osteoblasts and bone resorption by osteoclasts.

Question 11

A patient with a genetic defect in collagen synthesis would most likely have bones that are:

Accepted Answer

Very brittle and prone to fracture

Question 12

Which of the following is NOT a function of bone?

Accepted Answer

Synthesis of vitamin D

Question 13

Which type of cartilage is found in the intervertebral discs and menisci of the knee, and what is its main characteristic?

Accepted Answer

Fibrocartilage; has great tensile strength due to thick collagen fibers

Question 14

Which of the following best describes the process of intramembranous ossification?

Accepted Answer

Bone develops from a fibrous membrane.

Question 15

A patient has a fracture where the bone ends are out of normal alignment and the skin is penetrated. How would this fracture be classified?

Accepted Answer

Displaced, open (compound)

Question 16

Which of the following equations correctly represents the negative feedback loop for blood calcium regulation involving PTH?

Accepted Answer

$$	ext{Low blood } Ca$$^{2+}$$ ightarrow 	ext{PTH release} ightarrow 	ext{Osteoclast activation} ightarrow 	ext{Increased blood } Ca$$^{2+}$$

Question 17

Which of the following best explains why the diaphysis of long bones is hollow?

Accepted Answer

Because compression and tension cancel each other out in the center, reducing the need for bone material

Question 18

Which of the following is a correct sequence of events in the healing of a bone fracture?

Accepted Answer

Hematoma formation → Fibrocartilaginous callus formation → Bony callus formation → Bone remodeling

Question 19

Which of the following best describes the role of osteocytes in bone?

Accepted Answer

They maintain the bone matrix and act as stress or strain sensors.

Question 20

Which of the following is a real-life consequence of sustained hypercalcemia?

Accepted Answer

Increased risk of kidney stones due to calcium salt deposits

Bones and Skeletal Tissues: Structure, Function, and Development

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