Which cell breaks down bone tissue during resorption?

Which cell breaks down bone tissue during resorption?

• A. Osteoclast
• B. Osteoblast
• C. Osteocyte
• D. Chondrocyte

Answer: (A)

Osteoclasts break down bone during resorption. These large, multinucleated cells attach to the bone surface and create a sealed, isolated area called the resorption lacuna. Within this space they excrete acid and proteolytic enzymes (notably cathepsin K) that dissolve the mineral component of bone and digest the organic matrix. This controlled breakdown clears old or damaged bone so osteoblasts can later lay down new bone tissue, continuing the remodeling cycle. Osteoclasts originate from hematopoietic precursors and are tightly regulated by signaling pathways like RANKL and osteoprotegerin to balance bone resorption. By contrast, osteoblasts are the cells that build bone by producing osteoid and promoting mineralization, osteocytes are mature bone cells embedded in the matrix that help sense mechanical load and coordinate remodeling, and chondrocytes are cartilage cells involved in cartilage formation and endochondral ossification, not in bone resorption.

Osteoclasts break down bone during resorption. These large, multinucleated cells attach to the bone surface and create a sealed, isolated area called the resorption lacuna. Within this space they excrete acid and proteolytic enzymes (notably cathepsin K) that dissolve the mineral component of bone and digest the organic matrix. This controlled breakdown clears old or damaged bone so osteoblasts can later lay down new bone tissue, continuing the remodeling cycle.

Osteoclasts originate from hematopoietic precursors and are tightly regulated by signaling pathways like RANKL and osteoprotegerin to balance bone resorption. By contrast, osteoblasts are the cells that build bone by producing osteoid and promoting mineralization, osteocytes are mature bone cells embedded in the matrix that help sense mechanical load and coordinate remodeling, and chondrocytes are cartilage cells involved in cartilage formation and endochondral ossification, not in bone resorption.