Question

Explain the role of osteoblasts and osteoclasts as it relates to bone resorption and deposition due to disuse and physical activity.

Answer 1

Osteoclasts are the cells of the bone responsible for bone resorption. They remove Calcium, organic and inorganic matter from the bone causing reduction in bone mass. Hence these cells are more active in destructive process of the bone.

Opposite to the osteoclasts are osteoblasts cells which are immature bone cells. These cells are responsible for deposition of Calcium phosphate and other organic and inorganic matters in the bone. These cells mature and convert into osteocytes. These cells are bone forming cells.

Mechanical stress due to physical activity increases mechanical stress on the bone that results in increased activity of osteoblasts than osteoclasts. This result in increased density of the bone.

Reduction of mechanical stress on bone inhibits osteoblast-mediated bone formation and accelerates osteoclast-mediated bone resorption, and leads to what has been called disuse osteoporosis.