PSIO 201 5th Edition Lecture 11 Outline of Last Lecture Bone Organization Outline of Current Lecture I Bone Growth II Interstitial Growth III Growth at epiphyseal plate IV Appositional Growth Current Lecture Bone Growth Bones in children are not fully developed so they will have more bones then adults more spaces Epiphyseal plate located in children but stops function as adut A Interstitial Growth growth from within cartilage growth in length at epiphyseal plate 1 Chondroblasts build matric and differentiate into chondrocytes in ECM 2 Chondrocytes divide into isogenic groups 3 Chondrocytes build matric and spread apart 4 Cartilage tissue grows from within Growth at Epiphyseal Plate 1 Interstitial growth of cartilage 2 Endochondral Ossification Layers include resting cartilage proliferating cartilage interstitial growth B 1 2 3 4 5 a b hypertonic cartilage calcified cartilage will be replaced with bone diaphysis bone Diaphyseal osteoclast will break down calcified cartilage Osteoblasts lay down spongy bone Chondrocytes continue to form cartilage matric at proliferating cartilage region Growth in length stops when chondroblasts and chondroclasts work faster that chondrocytes at proliferating zone and then epiphyseal plate closed and becomes epiphyseal line Appositional Growth growth in width Periosteal osteogenic cells differentiate into osteoblasts Osteoblasts build bone in outer surface and Endosteum Osteoclasts increase the diameter of marrows cavity Bone diameter and cortical width increase Osteons are added to periosteal side of bone by ridges in perosteum create grooves for peristeal blood vessels osteoblasts build now concentric lamellae inward toward center making new osteons
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