Lecture 18- Bone repair Flashcards
What is the process of bone repair?
1) Haematoma forms. Swelling+ inflammation occurs
Phagocytic cells+ osteoclasts remove dead+ damaged tissue
Macrophages remove blood clot
2)Soft callus of granulation tissue arises. (Rich in capillaries+ fibroblasts)
Fibroblasts produce collagen fibres while chondrocytes produce hyaline cartilage
Osteoblasts from periosteum+ endosteum invade fracture+ form spongy bone.
3) New trabecullae appear in soft callus.
Fibrocartilaganous cartilage converted to hard bony callus. (cancellous bone)
Endochondral ossification replace all cartilage with cancellous bone
Intramembranous ossification produces new cancellous bone in any gaps
4)Bone remodelling of cancellous bone into compact bone.
What are the different types of fracture?
- Transverse
- Linear
- Non-displaced
- Displaced
- Spiral
- Greenstick
- comminuted
Functions of bone?
Mechanical:
- Protects important+ delicate tissue+ organs
-Provide framework for shape of body
Form the basis of levers involved in movement
Synthetic-
- Haemopoiesis
Metabollic
-Mineral storage (Calcium+ phosphorus)
at storage (yellow bone storage)
Acid-base homeostasis (absorb/ release alkaline salts to regulate blood Ph)
Importance of vitamin D?
Vitamin D3 absorbed by gut and produces calcitriol which is important for calcium absorption
Osteogeneis imperfecta?
- Mutation in COL1A gene
- Incorrect production of collagen 1 fibres
- Weak bones_ increased fracture risk
- Shortened height+ stature
- Blue sclera
Rickets?
- Vitamin D deficiency in children
- poor calcium mobilisation+ innefective mineralisation
- Weakened bone development
- Soft bones
- Bowed legs
- Shortened height and stature
Osteomalacia?
- Adults rickets
- Vitamin d deficiency
- lower mineralisation, increased osteoid
- Increased calcium resorption
- Caused by:
- kidney disease (activates Vit D)
- Protection from sunlight (produces Vitamin D)
- Surgery (Stomach and intestine)
- Drugs (Phenytoin prevents Vit D absorption
Achondroplasia?
- Mutation in FGF3 receptor gene
- Disrupts collagen formation from cartilage
- Affects endochondral ossification
- Short stature+ normal sized head and torso.
Osteoporosis type 1 (Primary) (weakening of bones until they break easily)
- Postmenopausal women
- Loss of oestrogen
- Increase in osteoclast number
Osteoporosis type 2 (Primary)
-Older men/women
Loss of oseoblast function
-Loss of both oestrogen+ androgen
What is secondary Osteoporosis?
Secondary osteoporosis is defined as bone loss that results from specific, well-defined clinical disorders (Hyperparathyroidism)
- from drug therapy (corticosteroids)
- Affects bone remodelling
What is intramembranous ossification?
1) MSC form a tight cluster
2) MSCs transform into osteoprogenitor cells, transform osteoblasts
3) Osteoblasts lay down osteoid
4) Osteoid mineralise to form spicules
5) Spicules link up to form trabeculae
6) Trabecullae replaced by the lamellae of mature compact bone
