Question at position 5 Exercise promotes development of bone mineral density and protects against osteoporosis because:exercise inhibits osteoclast activity so reduces bone resorptionexercise stimulates osteoblast activity so promotes bone depositionexercise inhibits osteoblast activity so reduces bone resorptionexercise stimulates osteoclast activity so promotes bone depositionClear my selection

Question

Question at position 5 Exercise promotes development of bone mineral density and protects against osteoporosis because:exercise inhibits osteoclast activity so reduces bone resorptionexercise stimulates osteoblast activity so promotes bone depositionexercise inhibits osteoblast activity so reduces bone resorptionexercise stimulates osteoclast activity so promotes bone depositionClear my selection

BlackTom AI · Accepted Answer

Mechanical loading of bone stimulates osteoblasts to lay down new bone matrix and increase mineral density, so exercise promotes bone deposition.

1) Relevant knowledge points and concepts
- Bone remodeling is a balance between osteoblasts (cells that build bone by producing osteoid and enabling mineralization) and osteoclasts (cells that resorb bone).
- Wolff’s law and mechanotransduction: bone adapts to the loads placed on it; strain sensed by osteocytes triggers signals that recruit and activate osteoblasts.
- Increased osteoblast activity and matrix mineralization raise bone mineral density (BMD) and reduce risk of osteoporosis.

2) Step-by-step reasoning
- Weight-bearing or resistance exercise imposes mechanical strain on bone.
- Osteocytes detect this strain and release biochemical signals (e.g., prostaglandins, NO, Wnt pathway activation).
- Those signals stimulate osteoprogenitor cells and osteoblasts to increase collagen/osteoid production and mineral deposition.
- Over time, increased bone formation outpaces resorption in regions experiencing load, raising net BMD.
- Higher BMD strengthens bone structure and lowers fracture risk associated with osteoporosis.

3) Calculations
- No numerical calculation is required for this conceptual question; the argument is based on cellular responses and tissue adaptation.

4) Why the correct answer is correct
- "Exercise stimulates osteoblast activity so promotes bone deposition" directly describes the primary adaptive mechanism: mechanical loading increases osteoblast-mediated bone formation, which increases BMD and protects against osteoporosis.

5) Why the other options are incorrect
- "Exercise inhibits osteoclast activity so reduces bone resorption": while exercise can indirectly influence resorption, the main protective effect is via stimulated bone formation by osteoblasts; the option implies only inhibition of resorption, which is not the principal mechanism presented.
- "Exercise inhibits osteoblast activity so reduces bone resorption": self-contradictory and false— inhibiting osteoblasts would reduce bone formation, worsening BMD.
- "Exercise stimulates osteoclast activity so promotes bone deposition": stimulating osteoclasts increases resorption, which would lower BMD, not promote deposition.

Conclusion: The correct choice is "exercise stimulates osteoblast activity so promotes bone deposition," which matches the provided answer.

类似问题

True or False: Osteoblasts are responsible for building new bone tissue, while osteoclasts break down bone and release calcium (Ca²⁺) into the bloodstream.

What effect do gravity and muscle tension have on bone?

Question at position 25 What role does Vitamin A play in bone growth and remodeling?It assists with protein synthesis.It stimulates osteoblast activity.It aids in calcitriol production.It helps synthesize collagen.

Which type of cells would be involved in bone remodeling in adults?

True or False: If osteoblasts are more active than osteoclasts in a given bone, the bone mass will decrease.

Why would running and jumping have a larger effect on bone health than walking?

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