Biology, Genetics & Bone Healing MCQs

A surgeon elects to use demineralized bone matrix (DBM) to augment a posterolateral lumbar spinal fusion. Based on its biologic properties, which of the following accurately describes the healing potential of this graft material?

A 70-year-old woman is prescribed daily subcutaneous teriparatide injections for severe osteoporosis. What is the primary cellular mechanism by which intermittent administration of this agent increases bone mineral density?

Romosozumab is a potent anabolic agent utilized in osteoporosis treatment that works by neutralizing sclerostin. In normal bone biology, which cell type is the primary source of sclerostin secretion?

A surgeon applies recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) on a resorbable sponge to treat a recalcitrant nonunion. Which intracellular signaling pathway is primarily activated when rhBMP-2 binds to its target cell surface receptor?

Denosumab is utilized in the management of osteoporosis and certain skeletal-related events in metastatic bone disease. It alters bone biology by directly binding to and inhibiting which of the following molecules?

Sclerostin, a glycoprotein produced primarily by mature osteocytes, serves as a negative regulator of bone formation. It achieves this by inhibiting which of the following intracellular signaling pathways?

Which type of fracture healing is primarily achieved when absolute stability and rigid internal fixation (e.g., a lag screw and neutralization plate) are applied to a simple fracture pattern?

Bone morphogenetic proteins (BMPs) exert their potent osteoinductive effects by binding to cell-surface receptors and primarily activating which of the following intracellular signaling molecules?

While most of the appendicular skeleton develops via an intermediate cartilage model, which of the following bones develops primarily via intramembranous ossification?

Osteoclasts are specialized multinucleated giant cells responsible for the resorption of bone matrix. From which distinct cellular lineage do osteoclasts originate?

During the intracellular biosynthesis of collagen, vitamin C (ascorbic acid) is an absolute requirement as a cofactor for which specific enzymatic process?

What process characterizes creeping substitution during the incorporation of a cortical bone graft?

What is the primary cellular mechanism of action for nitrogen-containing bisphosphonates?

Which type of fracture healing is characterized by the sequential formation of a soft cartilaginous callus followed by a hard bony callus?

Osteoclasts are multinucleated giant cells derived from which of the following cellular lineages?

A patient with severe, prolonged vitamin D deficiency develops osteomalacia. Which of the following serum laboratory profiles is most characteristic of this condition?

Osteoclasts bind to the bone matrix to initiate resorption by forming a sealing zone. Which specific integrin receptor on the osteoclast membrane is primarily responsible for binding to osteopontin and bone sialoprotein to create this sealing zone?

Bone remodeling is strictly regulated by intercellular communication between osteoblasts and osteoclasts. Which of the following molecules acts as a decoy receptor for RANKL, thereby inhibiting osteoclastogenesis?

Osteocytes secrete a protein called sclerostin to regulate bone mass in response to mechanical loading. Sclerostin inhibits osteoblastic bone formation primarily by antagonizing which intracellular signaling pathway?

A diaphyseal tibia fracture is treated with a cast. According to Perren's strain theory, what biomechanical environment is necessary to promote secondary bone healing with robust callus formation?