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