Q: Which of the following equations correctly represents the relationship between calcium homeostasis and parathyroid hormone (PTH) activity?

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

Question 1

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

Accepted Answer

Osteoclasts resorb bone by secreting lysosomal enzymes and protons (H+), breaking down bone matrix.

Question 2

A patient presents with bowed legs and enlarged, abnormally long bone ends. Laboratory tests reveal a vitamin D deficiency. Which condition is most likely present?

Accepted Answer

Rickets

Question 3

Which hormone is primarily responsible for stimulating osteoclast activity in response to low blood calcium levels?

Accepted Answer

Parathyroid hormone (PTH)

Question 4

During endochondral ossification, what is the correct sequence of events?

Accepted Answer

Formation of hyaline cartilage model, formation of bone collar, calcification of cartilage matrix, invasion of periosteal bud, formation of secondary ossification centers

Question 5

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

Accepted Answer

Condyle – rounded articular projection involved in joint formation

Question 6

A 70-year-old woman suffers a hip fracture after a minor fall. Her bone density scan shows significant loss of spongy bone in the femoral neck. Which disease is most likely responsible?

Accepted Answer

Osteoporosis

Question 7

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

Accepted Answer

It stimulates osteoblasts to deposit more bone matrix in response to mechanical stress, increasing bone mass.

Question 8

Which of the following is a correct statement about the chemical composition of bone?

Accepted Answer

Collagen fibers in osteoid provide tensile strength and flexibility.

Question 9

A child’s X-ray shows an epiphyseal plate with a thickened proliferation zone and a thin ossification zone. Which hormone imbalance could explain this finding?

Accepted Answer

Deficiency of thyroid hormone

Question 10

Which of the following equations correctly represents the relationship between calcium homeostasis and parathyroid hormone (PTH) activity?

Accepted Answer

$$	ext{Low blood } Ca$$^{2+}$$ ightarrow 	ext{PTH secretion} ightarrow 	ext{Osteoclast activation} ightarrow 	ext{Bone resorption} ightarrow 	ext{Increased blood } Ca$$^{2+}$$

Question 11

Which of the following best describes the process of appositional growth in bones?

Accepted Answer

Osteoblasts beneath the periosteum secrete bone matrix on the external surface, increasing bone thickness.

Question 12

A patient with a bone fracture undergoes the following sequence: hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling. Which stage involves the activity of phagocytic cells and fibroblasts secreting collagen fibers?

Accepted Answer

Fibrocartilaginous callus formation

Question 13

Which of the following statements about bone remodeling is correct?

Accepted Answer

Bone remodeling involves both bone deposit by osteoblasts and bone resorption by osteoclasts.

Question 14

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 markings.

Question 15

Which of the following is a distinguishing feature of fibrocartilage compared to hyaline cartilage?

Accepted Answer

Fibrocartilage contains thick collagen fibers, providing great tensile strength.

Question 16

A 25-year-old athlete experiences a spiral fracture of the tibia. Which of the following best describes this type of fracture?

Accepted Answer

Ragged break occurs when excessive twisting forces are applied to a bone.

Question 17

Which of the following statements about the periosteum is correct?

Accepted Answer

The periosteum is a double-layered membrane covering the external surface of bone except at joints, and contains osteogenic cells.

Question 18

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

Accepted Answer

Osteocytes are mature bone cells that maintain the bone matrix and act as stress sensors.

Bones and Skeletal Tissues: Structure, Function, Development, and Disorders

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드