Bone and Fracture Repair Flashcards Preview

1.1.1. Body Logistics > Bone and Fracture Repair > Flashcards

Flashcards in Bone and Fracture Repair Deck (17)
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1
Q

What is the difference between intramembranous ossification and endochondral ossification?

A

IMO: THICKENING, at mesenchymal tissue to form compact bone

EO: replacement of pre-existing hyaline cartilage template by compact bone

2
Q

How does intramembranous ossification take place?

A
  1. Mesenchymal stem cells –> osteoprogenitor cell –> osteoblasts,
  2. osteoblasts lay down osteoid (ECM: collagen I)
  3. osteoid calcifies forms spicules
  4. spicules form trabeculae which are replaced by lamellae of compact bone
3
Q

What are the two types of bone?

A

COMPACT: external surfaces, osteons = successive concentric lamella – resists bending – osteocytes spread between. At the centre is the haversian canal: contain blood vessels/nerves.

TRABECULAR: resists compression – osteocytes/bone marrow spread between, sense changes in strength, covered in lining cells, no haversian or Volkmann canals

4
Q

What is the difference between immature vs mature bone?

A

I –> random osteocytes, M –> osteocytes arranged in concentric lamellae of osteons, resorption canal runs parallel with osteons’ long axes

5
Q

Where is the site of haematopoiesis?

A

Bone marrow

6
Q

Which type of bone contains blood vessels?

A

Compact/cortical

7
Q

What is the role of osteoclast?

A

multi-nucleated cells, absorb bone, anchor to the surface of bone, ‘sealed-zone’ between osteoclast and bone, microenvironment, H+ and lysosomal enzymes: dissolves bone mineral content, enzymes then remove collagen matrix

8
Q

Describe what an osteoblast does

A

refill resorption cavities, deposit osteoid (collagen, Ca, phosphate begin to crystallise), some become trapped becoming osteocytes, some undergo apoptosis, some become lining cells on the surface of bone

9
Q

What is osteocyte?

A

Osteocytes: complex network throughout bone, sense increase workload on bone = trigger activation of osteoblasts. Reduced loading = resorption/remodelling increase to eliminate under-loaded bone

10
Q

What are the stages of bone repair when a break has occurred?

A

Break: bleeding = haematoma (eventually removed by macrophages), inflam, granulation tissue arises, blood vessels infiltrate, hyaline cartilage = fibrocartilaginous callus, Endochondral/intramembranous ossification = trabecular bone, remodelled to compact bone, bulging removed by osteoclasts

11
Q

What are the risk factors for osteoporosis?

A

age, female, post-menopausal, insufficient Ca intake, insufficient Ca absorption and Vit D, low exercise, smoking, genetic

12
Q

What is osteoporosis?

A

Metabolic bone disease = mineralized bone is decreased in mass, no longer provides support. Changes –> enhanced bone resorption, incomplete filling of osteoclast resorption bays, loss of mass in trabecular = increased risk of fracture

13
Q

What is the difference between type 1 and type 2 primary osteoporosis?

A

Primary osteoporosis type 1: post-menopausal women = increase in osteoclast number = oestrogen withdrawal. Primary osteoporosis type 2: elderly, both sexes (senile osteoporosis), reflects attenuated osteoblast activity

14
Q

What is periosteum?

A

Dense connective tissue enveloping bone except at the surface of joints

15
Q

What is diaphysis?

A

Shaft of bone

16
Q

What is metaphysics?

A

Wide region between epiphysis and diaphysis

17
Q

What is epiphysis?

A

Head of the bone