Lecture 8 Flashcards
Bone develops as a:
Cartilginous model
Transforming cartilage to bone is called?
Ossification
Where does the primary centre of ossification occur?
Diaphysis (shaft of bone)
Where does the secondary centre of ossification occur?
Epiphyseal plates - growth plates
What is the layer of cartilage that remains until bone growth is completed?
Epiphyseal plates
What does the epiphyseal plate do?
Allow bone to increase in length
How does bone increase in width?
Osteoblasts build bone beneath the periosterum, while osteoclasts break down bone from the endosteum
What causes Osteoporosis?
Abnormal bone turnover
How does Osteoporosis occur?
When osteoclast activity outweighs osteoblast activity
How does Osteoporosis affect bones?
Compact bones becomes thinner. Cancellous bone loses volume - becomes porous
A compound/open fracture is when:
bone breaks through the skin - open to the external environment.
A simple/closed fracture is when:
broken bone does not break the skin
A green stick fracture is when:
A partial break occurs - bone splinters. ONLY occurs in CHILDREN
What are the four stages of healing fractures?
- Haematoma. 2 Formation of soft callus. 3.Formation of hard callus. 4. Bone remodelling
What happens during step 1) Haematoma, of fracture healing?
Blood clots. blood vessels running through bone break when bone is broken and then clot
- blood clot forms haematoma
- capillaries run into haematoma
- phagocytes clear up dead tissue
What happens during step 2) Soft callus formation, of fracture healing?
Fibroblasts (which make collagen) and chrondoblasts (which make cartilage) form a soft callus
What happens during step 3) Hard callus formation, of fracture healing
Osteoblasts build bone tissue forming a hard callus.
What happens during step 4) remodelling of bone, of fracture healing
Remodelling occurs via osteoblast and osteaclasts
What is the time frame for stage 1) Haematoma of fracture healing?
0 - 3 days
What is the time frame for stage 2) Soft Callus formation of fracture healing?
3 days -2 weeks
What is the time frame for stage 3) Hard callus formation of fracture healing?
3 - 4 weeks
What is the time frame for stage 4) bone remodelling of fracture healing?
2 years ( bone completely healed after 2-3 months then bone remodelling occurs)
