Bone Flashcards
2 Types of Macroscopic Bone
- Cortical
2. Cancellous
Structure of Cortical bone
Osteons/Haversian systems 1. Osteon - outer border = cement lines 2. Vascular canals = Haversian canals (long axis) Volkmanns canals (TV) 3. Interstitial Lamellae
Cortical bone charactertics (2)
Slow turnover rate
High Youngs modulus
Cancellous bone characteristics
High turnover rate
Lower Youngs Modulus
2 types of Microscopic bone
- Woven Bone
2. Lamellar bone
Lamellar vs Woven bone features
Lamellar = remodelled bone
Organised
Stress oriented
Stronger and less flexible;
Osteoblasts origin
Undiff mesenchymal cells
OB function
Form bone - produce non-mineralised matrix
CK that stimulate OB formation (4)
BMP - Mesenchymal - osteoprogenitor cells
- RUN x2
- CBFA (core bind fac alpha)
- PDGF
- IDGF
Bump, run and core
Periosteum layers (2)
- Inner cambium layer
2. Outer fibrous layer
OB features
- Great synthetic ability
2. High ALP activity
3 fates of OB
- Inactive bone lining cells
- Osteocytes
- Apoptosis
Osteocyte functions (3)
- Control calcium
- Phosphate metabolism
- Respond to mechanical, electrical and chemical (PTH) stimuli
OB receptors (2)
- PTH
2. 1,25 dihydroxyvit D
PTH effect on OB (2)
Stim production of RANKL
Jagged1- Notch immune response
OC origin
Myeloid hamatopoieitic cells
Monocyte progenitor
OC microscopic appearance
Multinucleated giant cells