Chapter4CartilageandBone.ppt

组织胚胎学课件 七年制英文医学班专用,中国医科大学基础医学院组胚英文教学组,Chapter 4 Cartilage and Bone,1.Cartilage:organ=Cartilage tissue+perichondrium,1)structure of cartilage tissue-cell:chondrocyte-cartilage matrix,chondrocyte:-Structure:LMembedded in cartilage lacunaperipheral cells:-small and immature-single and flattenedcentral cell:-large and mature,-round and in group of 2-8 cells-small and round nucleus-basophilic cytoplasm-EM:rich in RER and Golgi complex,*isogenous group:several cells locates in one lacuna,which are derived from a single(same)parent cell,Cartilage matrix-ground substance:proteoglycan:-same to loose CT-there are more chondroitin sulfate distributed at the periphery of cartilage lacuna-called as cartilage capsule(basophilic)chondronectinwater-fiber:type and number of fiber depends on the type of cartilage,2)Classification:according to the fiberHyaline cartilage:less collagenous fibriltype II collagenarticular surface,rib cartilage,trachea and bronchi,Fibrous cartilage:large amount of collagenous fiber bundles cells are small and lessintervertebral disc,symphysis pubis,Elastic cartilage:large amount of elastic fiberexternal ear,epiglottis,3)perichondriumtwo layers:-out layer:contain more fiber-protection-inner layer:more cells-osteoprogenitor cell(fusiform in shape),4)growth of cartilage-interstitial growth:inner chondrocyte proliferation produce fiber and matrix.immature cartilage-appositional growth:osteoprogenitor cellcartilage cell(chondrocyte)produce fiber and matrix.growing and mature cartilage,2.Bone-consists of bone tissue,periosteum and endosteum,bone marrow,1)Bone tissue Cells:,a.osteoprogenitor cell:stem cell-structure:fusiform,small ovoid nucleusslight basophilic cytoplasmexist in periosteum and endosteum-function:differentiated into osteoblast and chondrocyte,b.osteoblast:-structure:LM:single layer of cuboidal or low columnar cellround nucleusbasophilic cytoplasmlocated on the surface of bone tissue,EM:fine processesrich in RER,Golgi complex,-function:.synthesize bone collagen fiber and ground substance-osteoid.release matrix vesicle:0.1um in diameter membrane-coated ALPase(Alkaline phosphatase),ATPase and pyrophosphatase and phosphoester(phospholipid)calcium,crystal of bone salt and calbindin function:promote calcification,c.osteocyte-structure:flattened cell with multiple long thin processeslocated in bone lacuna and bone canaliculusbasophilic cytoplasmadjacent cells connect in bone canaliculus by gap junctions-function:Maintain bone matrixregulate the balance of calcium and phosphonium,d.osteoclast-structure:LM:multinuclear large cell,30-100um 6-50 nuclei acidophilic cytoplasm located at peripheral part of bone,EM:ruffled border-processes light zone:-under the ruffled border-microfilament primary lysosome,pinosome and secondary lysosome RER,mito.and Golgi-function:dissolve and absorb bone matrix,Bone matrix-organic matter:bone collagen fiber-collagenous fiber(type I collagen)ground substance:glycosaminoglycan,glycoproteins:osteocalcin:involve in calcification of bone and regulate absorption of bone osteonectin:related to adherence between cell and bone matrix,regulate calcification of boneosteopontin,-inorganic matter:bone saltsHydroxyapatite crystal:Ca10(PO4)6(OH)2 pin-shaped 10-20 nm longitudinal arranged*bone lamella:bone matrix arranged in layers at different direction,2)Architacture of long bone Long bone is an organ,made up of bone tissue(shaft and epiphyses),periosteum and endosteum,bone marrow,shaft:consists of compact bone a.circumferential lamella:/outer concentrically-arranged/inner around inner surface of bone,b.Haversian system(osteon):/cylindric structure,3-5mm/central canal:N,BV,CT/Haversian lamella:4-20 layers,c.interstitial lamella:/irregular lamella/remnant of Haversian or circumferential lamella*perforating canal:/transverse canal/connect with Haversian canal,epiphyses:composed of spongy bone-trabeculae:formed by parallelly-arranged lamellaform a spongy-liked network-Bone marrow:hemopoietic tissue,periosteum and endosteum:CT membrane-periosteum:DCTouter layer:more fiber bundles form perforating fiberinner layer:rich in BV,N and osteoprogenitor cells-endosteum:thin,a layer of osteoprogenitor cell and CT-function:provide nutrition and osteoblast for bone growth and repairing,3)osteogenesis,basal processes-formation:osteoprogenitor cell osteoblast osteoid calcification osteocyte+bone matrix bone tissue-absorption:osteoclast dissolve bone tissuereconstruction,basal mannera.intramembranous ossification:-CT membrane osteoprogenitor cell osteoblastossification centerbone trabeculae thicker and longer-flattened bone and irregular bone formed in these manner,b.endochondral ossification:e.g.long bone.formation of cartilage model Mesenchymal cellosteoprogenitor cell chondroblastchondrocytecartilage model(consists of hyaline cartilage and perichondrium).formation of bone collar osteoprogenitor cell(perichondrium)osteoblast bone tissue*These bone tissue surround the central segment of cartilage model as collar-shaped,so called bone collar,.formation of primary ossification center and bone marrow cavity chondrocytes of model center stop differentiation,enlarge in size,calcification,dead CT,BV in periosteum enter degenerating zoneosteoblast,osteoclast,osteoprogenitor cell and mesenchymal cell enter at same timeossificationprimary ossification center,primary bone marrow cavity(space between trabeculae)bone marrow cavity,.Formation of secondary ossification center and epiphyses secondary ossification center appears at the two end of long bone(epiphyses)epiphyseal plate:cartilage layer between epiphysis and bone shaft,growing zone,Further growth of bone-Become longer:by growth of epiphyseal plate from epiphyses to shaft,four zones can be seen:i.reserve cartilage zone:cell is small,round and basophilicii.proliferating cartilage zone:cell is flattened,isogenous group cell arrange in single line,iii.calcified cartilage zone:cell become large,mature,round and degenerated,strong basophiliciv.ossification zone:-become thicker:periosteum cell osteoprogenitor cellosteoblast,