Anatomy - Broken arm Flashcards
What is compact bone?
Outer bone
What is trabecular bone?
Spongy middle part of a bone
Keeps bone as light as possible
A stage as reinforcement
What is the diaphysis?
Shaft of the bone
What is the epiphysis?
Head of the bone
What are the properties of bone?
- Reservoir of calcium and phosphate
- Composed of cells and ECM
- Bone marrow supports haematopoieisis
What are the properties of organic/osteoid matrix?
- Produced by osteoblasts
- Type 1 collagen
- Tensile and compressive strength
- Non-collagenous proteins mediated mineral deposition
What are the properties of inorganic matrix?
- Calcium phosphate
- Deposited in organic matrix
- 66% of dry weight of bone
- Hardness
What are 3 disorders related to bone composition?
- Brittle bone disease
- Osteopetrosis
- Osteoporosis
What are osteoprogenitor cells?
Stem cells forming osteoblasts
What are osteoblasts?
Immature bone cells that secrete organic components of matrix
What are osteocytes?
Mature bone cells formed from osteoblasts, which maintain matrix
What are osteoclasts?
- Multinucleated macrophages acting as scavengers of unwanted material
- Remove matrix and rebasorb bone
- Minerals are dissolved by acids
- Lysosomal enzymes reabsorb organic matrix
- Oestrogen reduces activity (linked to menopause)
What causes osteoid mineralisation?
Mineral precipitated from matrix of vesicles containing calcium and phosphate
What are the properties of immature osteoid mineralisation?
- Woven bone
- Haphazard fibre arrangement
- Mechanically weak
- Foetal development/fracture repair
What are the properties of nature osteoid mineralisation?
- Lamellar bone
- Remodelled woven bone
- Regukar parallel collagen
- Strong
- All adult bone
- Arranged as osteons
What are the main parts of this osteon?
What are the main parts of this to remember?
When does bone turnover increase?
- Change in function
- New demands
- Repair of fractures
- Disease
What is the relationship between osteoblasts and osteoclasts to remember?
What are the properties of intramembranous embryo bone development?
- Sheets of mesenchymal cells
- Differentiation into osteoblasts
- Trabecular bone formation
- Remaining mesenchyme makes bone marrow and periosteum
- Skull, maxilla and mandible bones
What are the properties of endochondral embryo bone development?
- Cartilage template
- Cartilage growth plate remains to allow bone lengthening
- Long bones and skull base
What are the gestational stages of cartilage and bone formation?
What are the differences between childhood, adolescence and adult bone formation?
What mesoderm are tje dermatome and myotome from and what do they give rise to?
Paraxial mesoderm
Dermatome = connective tissue of dermis
Myotome = limb muscles
What arises from the lateral plate mesoderm?
- Bones of upper and lower limbs
- Blood vessels
- Connective tissue
Where are sensory nerve elements derived from?
Neural crest
What is the first stage of limb growth?
Limb buds appear at 4 weeks
What is the second stage of limb growth?
- Most basic structures are established by 8 weeks
- From week 8 onwards, limb elements just grow in size
What planes do patterning, growth and maturation occur on?
- Proximal-distal
- Anterior-posterior
- Dorsal-ventral
Where is limb outgrowth initiated?
What does it depend on?
What happens if disrupted?
Apical ectodermal ridge
FGF signalling from AER
Arrested limb development
What does proximal-distal growth also depend on?
What can disruption lead to?
HOX genes
Loss of specific limb elements
