Osteoporosis results from which of the following?
A.
An increase in osteocyte activity while osteoblast activity continues at expected levels
B.
An increase in osteocyte activity while osteoclast activity continues at expected levels
C.
A decline in osteoblast activity while osteoclast activity continues at expected levels
D.
A decline in osteoclast activity while osteoblast activity continues at expected levels
The correct answer is:
C. A decline in osteoblast activity while osteoclast activity continues at expected levels
Explanation:
- Osteoblasts are the cells responsible for bone formation.
- Osteoclasts are the cells responsible for bone resorption, which is the process of breaking down bone tissue.
Osteoporosis occurs when there is a decline in osteoblast activity (bone formation), while osteoclast activity (bone resorption) either continues at the expected level or increases. This imbalance leads to a decrease in bone density and an increased risk of fractures.
- A. An increase in osteocyte activity while osteoblast activity continues at expected levels: This option is incorrect because osteocytes are mature bone cells that primarily maintain the bone matrix, not directly involved in the balance between bone formation and resorption.
- B. An increase in osteocyte activity while osteoclast activity continues at expected levels: This is incorrect for the same reason as above; osteocytes maintain bone, not actively build or resorb it.
- D. A decline in osteoclast activity while osteoblast activity continues at expected levels: This option would result in an increase in bone density, which is the opposite of osteoporosis.
Thus, osteoporosis results from C. A decline in osteoblast activity while osteoclast activity continues at expected levels.