1、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

2、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

3、 sulfate distributed at the periphery of cartilage lacuna-called as cartilage capsule(basophilic) water-fiber: type and number of fiber depends on the type of cartilage2) Classification: according to the fiberHyaline cartilage: less collagenous fibrilarticular surface, rib cartilage, trachea and bro

4、nchiFibrous cartilage:large amount of collagenous fiber bundles cells are small and lessintervertebral disc, symphysis pubisElastic cartilage: large amount of elastic fiberexternal ear, epiglottis3) perichondriumtwo layers: -out layer: contain more fiber-protection -inner layer: more cells-osteoprog

5、enitor cell(fusiform in shape)4) growth of cartilage-interstitial growth: inner chondrocyte proliferation produce fiber and matrix.immature cartilage-appositional growth:osteoprogenitor cellchondroblast chondrocyte produce fiber and matrix.growing and mature cartilage2.Bone-consists of bone tissue,

6、periosteum and endosteum, bone marrow1) Bone tissue Cells: a. osteoprogenitor cell: stem cell -structure: fusiform, small ovoid nucleusslight basophilic cytoplasmexist in periosteum and endosteum -function: differentiated into osteoblast and chondrocyteb. osteoblast: -structure: LM: single layer of

7、cuboidal or low columnar cellround nucleusbasophilic cytoplasmlocated on the surface of bone tissueEM: fine processesrich in RER, Golgi complex-function:.synthesize bone collagen fiber and ground substance-osteoid.release matrix vesicle: 0.1um in diameter membrane-coated function: promote calcificat

8、ionc.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 matrixd. osteoclast-structure: LM: multinuclear large cell, 30-100um 6-50 nucl

9、ei acidophilic cytoplasm located at peripheral part of boneEM: 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 matrixBone matrix-organic matter: bone collagen fiber

10、 -collagenous fiber (type I collagen) ground substance: glycosaminoglycan-inorganic matter: bone saltsHydroxyapatite crystal: Ca10(PO4)6(OH)2 pin-shaped longitudinal arranged*bone lamella: bone matrix arranged in layers at different direction2) Architacture of long bone Long bone is an organ, made u

11、p 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 la

12、mella: 4-20 erstitial 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: