15 Questions
What gives bone its rigidity?
Calcium hydroxyapatite
Which type of bone has a haphazard organization of collagen fibers and is mechanically weak?
Woven bone
What type of bone is found at the ends of the diaphysis and provides maximum blood supply?
Metaphysis
Which component of bone is responsible for giving it elasticity?
Collagen
What is the function of trabecular bone within bone structure?
Support and movement
Which type of bone formation occurs within 2 weeks after a fracture?
Primary bone healing
What initiates the formation of chondroblasts and osteoblasts during fracture repair?
Transforming growth factor β
Which factor stimulates angiogenesis during the fracture healing process?
Fibroblastic growth factor
In which phase of fracture healing does direct generation of woven bone occur?
Repair phase
Which cells are responsible for synthesizing new osteoid at a rate of 1 micron per day?
Osteoblasts
What is the primary characteristic of primary bone healing as opposed to secondary bone healing?
Rigid fixation
'Type II collagen, then Type 1 collagen expression in unstable patterns' is associated with which phase of fracture healing?
Repair phase
'Linear resorption rate of 50 microns per day' is a feature associated with which type of bone healing?
Secondary bone healing
'Osteoclastic resorption, possibly guided by electrical or mechanical strain fields' occurs during which phase of bone healing?
'Haversian Remodelling' phase
What role does Transforming growth factor β play in the fracture healing process?
Stimulates angiogenesis and chondroblast formation
Study Notes
Bone Structure and Fracture Healing
- Bone consists of living cells embedded in a mineralized organic matrix, comprising collagen, calcium hydroxyapatite, and other calcium phosphates.
- The inorganic content of bone provides rigidity, while the organic content provides elasticity.
- Bone functions include supporting movement, protection, haematopoiesis, storing minerals and fat, and endocrine regulation.
Types of Bones
- Long bones provide strength, support, structure, and mobility, as well as bearing body weight.
- The metaphysis is located at the ends of the diaphysis, where there is a maximum blood supply, and the physis is the cartilage growth center.
Bone Classification
- There are two types of bone formation: intramembranous (primary) and endochondral (secondary).
Fracture Healing
- Fracture healing begins immediately and continues for many years, resulting in a mineralized mesenchymal tissue.
- The process involves many stages, including inflammation, bleeding, haematoma, and granulation tissue formation.
- Osteoblasts proliferate and replace the haematoma, and the bony bridge forms, eventually becoming strong enough for functional needs.
Stages of Fracture Healing
- Inflammation: bleeding, haematoma, and growth factors stimulate fibroblasts and mesenchymal cells.
- Repair: osteoprogenitor cells and fibroblasts proliferate, and a bony bridge forms.
- Remodeling: begins during the middle of the repair phase and continues for up to 7 years, according to Wolff's Law.
Factors Affecting Fracture Healing
- Age, comorbidity, blood supply, nicotine, NSAIDs, nutrition, vascular injury, soft tissue envelope, functional level, nerve function, hormones, and site/location can all impact fracture healing.
- Primary bone healing, which occurs with rigid fixation, has a temporary acceleration of Haversian remodeling, with no callus formation.
Low-Intensity Ultrasound in Fracture Healing
- Pulsed low-energy ultrasound may enhance fracture healing by inducing angiogenesis and expressing IL8, basic FGF, and VEGF, reducing healing time by up to 38%.
Explore the composition of bone, including living cells and mineralized organic matrix, and understand how different components contribute to bone rigidity and elasticity. Learn about the functions of bone cells and the process of fracture healing.
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