Bone

Question 1

How do bisphosphonates work?

Answer 1

• Bisphosphonates bind to hydroxyapatite crystals on the bone.
• Osteoclasts then eat up these crystals containing bisphosphonate and die since bisphosphonates induce osteoclast apoptosis.
• Thus, bisphosphonates are considered antiresorptive.

Question 2

Summarize how osteoclasts and osteoblasts are made.

Answer 2

• Bone –> monocyte-macrophage lineage –> osteoclasts
• Bone –> mesenchymal stem cells –> osteoblasts

Question 3

Summarize the RANK-ligand signaling pathway.

Answer 3

• PTH stimulates osteoblasts to secrete RANK-ligand
• RANK-L binds to RANK on preosteoclasts (pushing them to develop into osteoclasts) and to RANK on osteoclasts to start resorbing bone.