6.8 Bone repair

Question 1

what happens most immediately after a bone break?

Answer 1

hematoma formation

-mass of blood, usually a clot

Question 2

What are the two types of calluses in bone repair?

Answer 2

internal and external

Question 3

describe the formation and fn of the internal callus during bone repair

Answer 3

fibroblasts produce collagen
vessels enter clot, bringing macrophages
osteoclasts break down dead bone
osteochondral progenitor cells from the periosteum and endosteum make chondroblasts which produce cartilage
osteochondral progenitor cells from the endosteum make osteoblasts which begin to produce new bone

Question 4

describe the formation of the external callus during bone repair

Answer 4

forms a collar around broken bones

osteochondral progenitor cells make osteoblasts and chondroblasts

Question 5

what happens in bone repair after callus formation?

Answer 5

callus ossification

Question 6

what happens during callus ossification

Answer 6

cartilage is replaced by woven, cancellous bone via endochondral ossification from within the cartilage

Question 7

what happens after callus ossification

Answer 7

bone is remodelled
woven bone is replaced by compact bone
medullary cavity is restored by osteoclasts