Interstitial Growth: Growth in Length of Long Bones
what will Epiphyseal plate thins be replaced by
epiphyseal plate closure
what zone is Relatively inactive
the Resting (quiescent) zone
what happens at the Proliferation (growth) zone
Cartilage on diaphysis side of epiphyseal plate Rapidly divide pushing epiphysis away from diaphysis lengthening
what happens at the Resting (quiescent) zone
Cartilage on epiphyseal side of epiphyseal plate- Relatively inactive
what happens at the Ossification zone
Chondrocyte deterioration leaves long spicules of calcified cartilage at epiphysis-diaphysis junction- Ultimately replaced with spongy bone
when does happen Appositional Growth Growth in Width
Growth in width occurs throughout life
what happens at the Calcification zon
Surrounding cartilage matrix calcifies, chondrocytes die and deteriorate
what happens at the when Ultimately replaced with spongy bone
Spicules eroded by osteoclasts Covered with new bone by osteoblasts
when in Interstitial Growth do chodndroblasts divide less often
Near end of adolescence chondroblasts divide less often
what happens at the Hypertrophic (excessive growth) zone
Older chondrocytes closer to diaphysis enlarge and erode interconnecting spaces
Osteoblasts function in Appositional Growth
Osteoblasts beneath periosteum secrete bone matrix on external bone
osteoclasts function in Appositional Growth
Osteoclasts remove bone on endosteal surface
what are the Result of five zones within cartilage of Interstitial Growth
Resting (quiescent) zone Proliferation (growth) zone Hypertrophic zon Calcification zone Ossification (osteogenic) zone
Osteoclasts involvment in bone weight in appositional growth
Usually more building up than breaking down Thicker, stronger bone but not too heavy