Karteikarten
Bone and Cartilage
Karten in diesem Stapel (17)
- 1CartilagePermeable to water and small molecules
Appositional and interstitial growth
BY VOLUME
25% - organic :
60% - collagen II, 40% GAGS + proteins
75% - water - 2BoneImpermeable
Only appositional growth
Needs blood supply
BY VOLUME
36% - inorganic
36% - organic
28% - water
BY WEIGHT
60% - inorganic
25% - organic
15% - water - 3Appositional GrowthFibroblasts in perichondrium can give rise to chondrocytes
- 4Interstitial GrowthChondrocytes in matrix also proliferate
- 5Bone MarrowYellow - stores fat
Red - forms blood cells - 6Bone structureNon-articular surfaces concerned by periosteum (CT of muscles blends with this)
Interbal surfaces lined by endosteum - 7Woven BoneImmature, irregular, in foetus, fracture repair
- 8Lamellar BoneCollagen sheets, compact (circumferential or Haversian system - small concentric layers around Haversian canal patterns) or spongy (aligned along lines of stress - maximises resistance to forces whilst minimises mass of bone)
- 9Osteoprogenitor CellsFibroblast-like, stem cell population for osteoblasts, in spongy, near blood vessels, in compact near periosteum and endosteum
- 10OsteoblastsOn bone surface, deposits osteoid (organic material), contact via desmosomes/gap junctions, make collagen I, also induce mineralisation through secretion of matrix vesicles, contain alkaline phosphatase (which neutralise inhibitory effects of PPi on calcium deposition), stops spontaneous calcification
- 11OsteocytesCell bodies in lacunae, number canals - canaliculi, osteocyte cell processes which provide communication, permits diffusion, calcium homeostasis, responsive to mechanical receptors
- 12Bone-lining cellsUndifferentiated, flattened cells at bone surface, quiescent
- 13OsteoclastsIn Howship's lacunae, multinucleate, highly motile, macrophage like, microvilli (secrete protons to demineralise matrix) surrounded by clear zone, form tight seal with bone surface, many mitochondria, many vesicles (which acid phosphatase), organic degraded by lysosomal proteins, inhibited by calcitonin, parathyroid hormones stimulate to osteoblasts to release osteoclasts
- 14Haversian System FormationOsteoclasts tunnel through pre-existing bone, invaded by blood vessels and osteoprogenitor cells (lay down osteoblasts, which lay down matrix, so get more osteoblasts), lay from inside
- 15Endochondral Ossificiation From pre-existing cartilage Start with bony collar around to cut off cartilage, so it calcifies, bone remodels and allows blood vessels etcNon-articular surfaces covered by perichondrium forms periosteum, (causes chondrocyte calcification), begins in centre, blood vessels invade shaft with osteoclasts (reabsorb calcified cavity to form medullary cavity - osteoblasts lay down on this) and osteoprogenior cells, proliferation of chondrocytes at epiphytes causes growth, growth plate
- 16Growth Plate Zones Growth plate between primary and secondary ossification centresZone of reserve cartilage - chondrocytes quiescent
Zone of proliferation - chondrocytes proliferate into longitudinal columns
Zone of hypertrophy and calcification - chondrocytes enlarge, matrix calcified
Zone of degeneration - chondrocytes die, lacunae invaded by osteoclasts, osteoprogenitor cells and capillaries
Osteogenic zone - osteoblasts lay bone on calcified cartilage - 17Inter-membranous Ossification Develop in mesenchymeDirect bone formation, begins as primitive mesenchymal cells, osteoblasts arise from differentiation and lay done bone, isolated spicules of bone coalesce
Informationen
- Beschreibung
- Karteikarten am Bone and Cartilage, erstellt von maryamnc am 04/01/2015.
- Erstellt von
- maryamnc
- Aufrufe
- 1
- Bewertung