The physis is responsible for growth in length of a long bone. Cells in the proliferating zone divide and add to the top of the chondrocyte column. Metaphyseal vessels in the resorbing zone advance into the lacunae of the terminal hypertrophic chondrocyte at the bottom of the column.
New bone is deposited on the remnants of the mineralized cartilage matrix in the ossification zone.
Physeal closure at skeletal maturity When the animal reaches skeletal maturity, the physis closes. Chondrocyte proliferation at the top of the cell columns stops. Metaphyseal blood vessels continue advancing until vasculature becomes confluent between the epiphysis and metaphysis. This image also shows secondary spongiosa which results from the remodeling of primary spongiosa. The bone of the primary spongiosa with central calcified cartilage is replaced by new lamellar bone during the remodeling process.