Page 290 - Atlas of Histology with Functional Correlations

B. Osteoprogenitor cells

C. Osteocytes

D. Fibrocytes

E. Osteoclasts

5. What function does the hormone calcitonin perform?

A. It activates osteoclast activity.

B. It decreases bone resorption and decreases calcium levels.

C. It stimulates osteoid and bone matrix formation.

D. It increases calcium absorption and raises calcium levels.

E. It stimulates parathyroid hormone production.

1. Correct Answer: B. The cartilage model grows by interstitial and
appositional means. Because the cartilage matrix is soft, cartilage during
endochondral ossification can grow in length and width by interstitial and

appositional growth methods.

2. Correct Answer: A. Epiphyseal plate. This soft plate allows the cartilage
cells to grow and lengthen the bone.

3. Correct Answer: C. Connective tissue mesenchyme. These cells form
ossification centers where the mesenchyme cells differentiate into

osteoblasts to form the bone.

4. Correct Answer: E. Osteoclasts. Parathyroid hormone indirectly influences
osteoclasts by acting first on the osteoblasts.

5. Correct Answer: B. It decreases bone resorption and decreases calcium
levels. Calcitonin counteracts the effect of parathyroid hormone, by

decreasing osteoclast activity and calcium resorption.

ADDITIONAL HISTOLOGIC IMAGES

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