Fichas
BMS09-1016 -Bone Growth, Modelling and Remodelling
Fichas del conjunto (18)
- 1When does bone MODELLING occur? What does it do?In the growing skeleton (eg. in children or during development)
It shapes the skeleton - 2Bone modelling is net.... where osteoclastic bone formation ... bone reabsorptionBone formaton
> is more than - 3When does bone remodelling occur? For what 3 reasons?In adults
1. Calcium homeostasis
2. Skeletal homeostasis
3. Adaptation to mechanical forces - 4When bone reabsorption>formation...occurs When bone reabsorption1. Osteoporosis
2. Osteopetrosis - 5In bone remodelling, how does bone mass change? Bone formation is .... to Bone reabsorptionNo net change in bone mass
equal, only occurs where there is bone reabsorption - 6What type of bone does 80% of bone remodelling occur in?Trabecular bone
- 7What is the process of Activation-Resorption-Formation (ARF)?1. Osteoclast precursors recruited to lining cells
2. Multinucleation
3. Preosteoclasts create sealing zones
4. Osteoclasts pump H+/Cl- into sealing zones
5. Osteoclasts die
6. Osteoblasts proliferate
7. Matrix made at reversal line, osteoid (unmineralised bone) forms
8. Mineralisation
9. Osteoblasts become osteocytes in lining cells or lining cells - 8What is Howship's Lacunae?The sealing zone wherein Osteoclasts pump in H+/Cl- to degrade bone
- 9What happens at the reversal line?Osteoclasts die and are replaced by osteoblasts, which start secreting matrix
- 10How does bone remodelling occur at the growth plate/metaphysis? Which bone is formed first: woven or lamellar?1. Cartilage is calcified for osteoclasts to reabsorb
2. First cycle is when when cartiledge is reabsorbed to form woven bone
3. Woven bone reabsorbed to form lamellar bone - 11Does reabsorption happen at the top or bottom of the growth plate/metaphysis?Bottom
Formation occurs at the top - 12What factors affect Bone Remodelling other than mechanical stress? (4)1) Systemic hormones
- Parathyroid hormone (Increase plasma Ca2+)
- Tri-iodothyronine
- Growth hormone
- Estrogen (lower bone breakdown)
2) Growth factors/cytokines
- Bone morphogenetic proteins
- Haematopoietic cytokines
3) Local factors
- Prostaglandins
4) Nuclear transcription factors
- Nuclear genes
- Mission control
- It instructs what to do (differentiate, proliferate, die) - 13According to Wolff's Law what determines the 3D structure of bone (mass/structure)?Mechanical stress; bone is laid out in areas of maximal tensile stress
- 14How does bone sense mechanical stress?Osteocytes are mechanoreceptors
- 15What are three bone diseases?1. Fractures
2. Osteoporosis
3. Paget's Disease - 16What is an example of mechanical loading in dentistry?Teeth moving in orthodontics
- 17What is the difference between Primary Spongiosa & Secondary Spongiosa1. Primary spongiosa is made of woven (immature) bone
2. Secondary spongiosa is made of Lamellar bone (closer to remodelling so closer to metaphysis) - 18What is Paget's Disease?- Too much osteoclasts
- Osteoblast cannot synthesise enough matrix
- Abundance of osteoid and woven bone
Información
- Descripción
- Define the terms ‘modelling’ and ‘remodelling’ as applied to the growth of bone. Understand why bones remodel. Explain the role of and interaction between osteoblasts and osteoclasts in bone remodelling. List the basic proteins/factors that control bone remodelling. Know Wolff’s Law and explain how mechanical forces can induce changes in bone architecture. Describe what may be learned about bone remodelling from a study of bone disease.
- Creado por
- Evian Chai
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