Which cells are primarily responsible for bone remodeling?

• A. Osteoblasts
• B. Osteocytes
• C. Osteoclasts
• D. Lining cells

Answer: (C)

Osteoclasts are the cells primarily responsible for bone remodeling because they are specialized in breaking down bone tissue through a process called bone resorption. These cells are large, multinucleated, and originate from monocyte/macrophage lineage, which allows them to efficiently export acid and enzymes that digest the mineralized matrix of bone. This is a critical function in maintaining bone health, as it allows for the removal of old, damaged, or unnecessary bone to make way for new bone formation.

During the remodeling process, osteoclasts work in conjunction with osteoblasts, which are responsible for bone formation, and osteocytes, which help regulate the activity of both osteoclasts and osteoblasts. However, it is the osteoclasts that directly carry out the resorption of bone, thus playing a pivotal role in the cycle of bone remodeling. Their activity is balanced by the actions of the other cells, ensuring that bone density and structural integrity are maintained throughout an individual's life.