组织与胚胎学双语课件骨与软骨.ppt

Chapter 4 cartilage and bone,Cartilage(软骨),Structure & Features Cartilage: Cartilage tissue + perichondrium Cartilage tissue: Cells + matrix (fibers+ g.s.) The g.s. is solid. No B.V., lymphatics & nerves. (It nourished by diffusion),3 types of cartilage: ( based on the type of fibers) hyaline cartilage(透明软骨) elastic cartilage(弹性软骨) fibrocartilage(纤维软骨) Function: support connection sliding surface for joints,1. Hyaline cartilage,Location: embryonic skeleton, articular surfaces, rib cartilage, larynx, trachea etc. Structure: A. Ground substance (基质) HE: basophilic (more chondroitin sulphate),trachea,Chemical composition is similar to that of L.C.T. ( 硫酸软骨素) Cartilage lacunae(软骨陷窝): matrix cavity Cartilage capsule (软骨囊): : on the surface of the lacunae; strong basophilic (硫酸软骨素较多),cap,B. Fibers Collagenous fibril (胶原原纤维 ) D=10-20nm invisible in LM (delicate & same refractive index as the g.s.) C. Chondrocytes (软骨细胞) Located in cartilage lacunae Basophilic,LM: Peripheral chondrocytes: less mature; small isogenous group (同源细胞群). EM: rich in RER. r., Mit. , developed Gl., Glycogen & lipid droplet. Function: synthesize f. & g.s.,C. Chondrocytes(软骨细胞),Perichondrium(软骨膜): Dense c.t.; Outer layer: more collagenous fibers; Inner layer: more b.v. & cells, osteoprogenitor cells chondroblast cells chondrocytes new cartilage tissue),Function: protection, nutrition, repairing,E. Cartilage growth & regeneration,Interstitial growth(内积性生长): Chondrocytes: increase the number of cells (mitosis) & the amount of matrix from within Appositional growth (外加性生长): : chondroblast cells in perichodrium produce new layer of cartilage tissue from outside,2. Elastic cartilage(弹性软骨),Location: external ear; epiglottis etc. Structure: elastic fiber (dense & closely packed) + chondrocytes Feature: more elasticity & flexibility,3. Fibrocartilage(纤维软骨),Location: intervertebral disk; symphysis pubis; end of tendons etc. Structure: collagenous fiber (A large number, in parallel bands), less g.s. & chondrocytes,Bone(骨),1. Characteristics: bone tissue + medullary cavity & bone marrow + periosteum & endosteum bone tissue= cells + bone matrix (fibers + calcified g.s.) hard & rigid support, protection, movement & for calcium storage,Organic (35%); inorganic (65%) Organic part: collagenous fibers (90%) amorphous g.s.: GSG (HA, chondroitin s., keratin s) Glycoproteins: osteocalcin(骨钙蛋白), osteonectin (骨粘连蛋白), osteopontin (骨桥蛋白). Function: responsible to resilience,2. Bone matrix(骨基质),Inorganic part (bone mineral,骨盐): mainly hydroxyapatite crystal(羟基磷灰石结晶) with the composition Ca10(PO4)6(OH)2 be responsible to hardness Bone lamellae(骨板) ： bone matrix arranged in plywood-like layers with fibers parallel or in right angles; apatite needles lie alongside the fibrils.,3. Cells,Osteoprogenitor cells(骨祖细胞 ) Osteoblasts(成骨细胞) Osteocytes(骨细胞) Osteoclasts (破骨细胞),A. Osteoprogenitor cell(骨祖细胞),Location: In periosteum & endosteum L.M.: Small, spindle shape, slightly basophilic Function: Stem cell, differentiate into osteoblast,B. Osteoblast(成骨细胞),Location: at surface of bone tissue in a layer; LM: cuboidal, low columnar, polygonal strong basophilic, large pale nuclear w/ obvious nucleolus EM: short processes rich in rER & Gl.,Osteoblast release matrix vesicle Osteoid Ca+ bone matrix Osteoblasts osteocytes,osteoblast fibers g.s osteoid (类骨质),Function:,C. Osteocyte (骨细胞),Location: embedded in calcified matrix LM: cell body: Flat processes: long fine, in canaliculi weak basophilic tissue fluid fills in bone lacunae(骨陷窝) & bone canaliculi(骨小管),EM: gap junction b/w connected processes for intercellular communication Function: Maintain Exchange the Ca 2+ b/w tissue fluid and blood,Osteoclast (破骨细胞),Location: In depression on the bone surface termed Howships lacunae LM: Giant cell, irregular, multinucleate (5-50), fusion of monocytes), acidophilic, ruffled border(皱褶缘),EM: Mv.(ruffled border); ring clear zone(w/ Mf.) Lysosomes; Phagocytosis vacuoles Others: Mit. rER.,Function: Clear zone(亮区): attached the bone surface to form a microenvironment Osteoclasts release lysosomal enzymes (proteinases, carbonic anhydrase), & acids (citric acid, lactic acid) to dissolve the bone matrix Mv.: increase the absorptive area & absorb the dissolved products * belong to the mononuclear phagocyte system,4. Bone structure,long bone diaphysis (骨干 ) (compact bone) epiphyses ( 骨骺 ) (sponge bone),A. Spongy bone(松质骨) Location: at the end & inner surface of a long bone Structure: Parallel lamellae trabeculae osteocytes spongy-like network. The canaliculi open to the marrow cavity,B. Compact bone(密质骨),Circumferential lamellae(环骨板) Osteon (Haversian system)(骨单位) Interstitial lamellae(间骨板),Structure: a. Circumferential lamellae： (环骨板) arranged in concentric circles. outer: 10-40 layers inner: fewer layers,Cylindrical units; 4-20 layers of Osteon lamellae (Haversian) Central canal中央管 (b.v. / n.f. / tissue fluid in it), canaliculi open to the canals; A cement line(粘合线) wraps around the unit; consist of mineralized matrix with few collagenous fibers,b. Osteon (Haversian system) 骨单位,Volkmanns canals (perforating canals,穿通管) communicate w/ the central canals.,c. Interstitial lamellae(间骨板):,Irregular lamellae b/w the osteons; It is the remnants of osteons during reconstruction.,I.L,os,5. Periosteum(骨外膜),outer layer: dense c.t., thicker; the perforating f(穿通纤维). (Sharpeys fibers) fix the periosteum to bone; inner layer: containing osteoprogenitor cells, small b.v. & n.,6. Endosteum(骨内膜),thin c.t. reconstruction,Histogenesis of bone(骨的发生),1) Intramembranous ossification (膜内成骨),parietal bone、frontal bone、clavicle mesenchymal cells membrane of CT osteoprogenitor cells osteoblast Osteoid osteocyte calcification osseous tissue (primary ossification center) Primitive bone trabeculae (woven bone) a layer of spongy bone resorption and remodeling 3 layers (inner and outer plates of compact bone and diploe bone in between).,2) Endochondral ossification (软骨内成骨) 1. formation of cartilage model(软骨雏形形成) mesenchymal cell osteoprogenitor cell chondroblast chondrocyte hyaline cartilage tissue perichondrium,middle part Inner cells of perichondrium (osteoprogenitor cells) Osteoblasts(secrete bone matrix) Lay down bone (bone collar) on outside of cartilage model. Responsible for increase in width and thickness of diaphysis.,2.Formation of bone collar(骨领形成),3. endochondral ossification (1) primary ossification center (初级骨化中心),Primary ossification center formed in the center of cartilage model Chondrocytes hypertrophy Cartilage matrix calcified Chondrocytes die Invasion of blood vessels and mesenchyme cells Removal of calcified cartilage by osteoclasts and formation of primary marrow cavity Osteoblasts lay down primary bone on calcified cartilage matrix remnants Ossification spreads toward the ends At this stage,the calcified cartilage appears basophilic,and the primary bone is eosinophilictransitional trabeculae.,(2) secondary ossification center(次级骨化中心):,epiphyseal plate : between diaphysis and epiphysis. responsible for increase in length of a long bone 4 zones: resting cartilage zone, proliferating cartilage zone, calcified cartilage zone and ossification zone,The 4 zones of epiphyseal cartilage (showing the continuous process of endochodral ossification):,resting cartilage zone: (软骨储备区) small chondrocytes