Bone Growth & Fracture Repair

What cell type is growing in the proliferation zone?

• Osteoblasts which are bone cells

• Osteoclasts which are cartilage cells

• Chondrocytes which are cartilage cells

• Osteocytes which are cartilage cells

What is happening in the "hypertrophic" zone?

• Bone cells are replicating

• Bone cells are enlarging

• Cartilage cells are replicating

• Cartilage cells are enlarging

Why do chondrocytes die during bone growth and elongation?

• Osteoblasts signal them to do so

• Osteocytes signal them to do so

• There is a reduction in nutrients

• There is a reduction in blood flow

What is a haematoma?

• Blood clot

• Blood loss

• Increased blood flow

• Reduced blood flow

What forms during the fibrocartilaginous stage of fracture repair?

• Fibrocartilage is converted to bone

• Osteoclasts remove excess bone

• Blood clot

• Chondroblasts make cartilage, fibroblasts make collagen

Why would load bearing begin around 4-6 weeks after a simple fracture?

• Its in the hard callus stage, bone is formed

• Its in the hard callus stage, fibroblasts need the stimulus

• Its in the remodelling stage, osteoblasts require stress

• Its in the remodelling stage, chondroblasts require stress