1、Cartilage and BoneCartilage and Bone 1.Cartilage:organ=Cartilage tissue+perichondrium 1)structure of cartilage tissue -cell:chondrocyte -cartilage matrix chondrocyte:-Structure:LM embedded in cartilage lacuna peripheral cells:-small and immature -single and flattened central cell:-large and mature,-
2、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 chon
3、droitin 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 cartilage 2)Classification:according to the fiber a.Hyaline cartilage:less collagenous fibril articular surface,rib cartilage,trachea an
4、d bronchi b.Fibrous cartilage:large amount of collagenous fiber bundles cells are small and less intervertebral disc,symphysis pubis c.Elastic cartilage:large amount of elastic fiber external ear,epiglottis 3)perichondrium two layers:-out layer:contain more fiber-protection -inner layer:more cells-o
5、steoprogenitor 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 cartilage 2.Bone-consists of bone t
6、issue,periosteum and endosteum,bone marrow 1)Bone tissue Cells:a.osteoprogenitor cell:stem cell -structure:fusiform,small ovoid nucleus slight basophilic cytoplasm exist in periosteum and endosteum -function:differentiated into osteoblast and chondrocyte b.osteoblast:-structure:LM:single layer of cu
7、boidal or low columnar cell round nucleus basophilic cytoplasm located on the surface of bone tissue EM:fine processes rich in RER,Golgi complex-function:.synthesize bone collagen fiber and ground substance-osteoid.release matrix vesicle:0.1um in diameter membrane-coated function:promote calcificati
8、on c.osteocyte -structure:flattened cell with multiple long thin processes located in bone lacuna and bone canaliculus basophilic cytoplasm adjacent cells connect in bone canaliculus by gap junctions-function:Maintain bone matrix d.osteoclast -structure:LM:multinuclear large cell,30-100um 6-50 nucle
9、i 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-colla
10、genous fiber(type I collagen)ground substance:glycosaminoglycan -inorganic matter:bone salts Hydroxyapatite crystal:Ca10(PO4)6(OH)2 pin-shaped 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 ti
11、ssue(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.int
12、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 lamella form a spongy-liked network-Bone marrow:hemopoietic tissue perios
13、teum and endosteum:CT membrane -periosteum:DCT outer layer:more fiber bundles form perforating fiber inner 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 Self study!