epiphyseal plate growth/zones

epiphysis, diaphysis

zones are number from closer to the ____________ to closer to the _____________

zone of resting cartilage

1st zone, closest to the end of epiphysis

small resting cells, does not actively participate in growth, anchors the epiphyseal plate to the epiphysis

describe cells in the 1st zone

zone of proliferating cartilage

2nd zone

slightly larger (than 1st zone) cells stacked like coins, divide and excrete extracellular matrix

describe cells in the 2nd zone

zone of hypertrophic cartilage

3rd zone

large maturing chondrocytes in columns

describe cells in the 3rd zone

zone of calcified cartilage

4th zone

only a few cells think, dead calcified chondrocytes

describe cells in the 4th zone

osteoclasts remove cartilage and osteoblasts build spongy bone, periosteum lays down compact bone

what happens at the end of the 4th zone