Reserve zone - Low oxygen tension. Gauchers, Diasttrophic dysplasia, pseudoanchondroplasia
Proliferative zone - Highest rate of matrix production due to proliferation of chondrocytes. Inccreased oxygen tension. Achondroplasia, gigantism, MHE
Hypertrophic zone - 3 zones. this is where Chondrocytes MATURE (zone), they then hypertrophy as they DEGENERATE (zone), and then eventually dis releasing their calcium and resulting in CALCIFICATION (zone).
Regulated by local growth factors
Type 10 collagxen important for mineralisation.
SUFE, Rickets (CZ), enchondromas, Fractures (CZ, esp SH 1)
Primary spongiosa (metaphysis) - vascular invasion, OB minerilise to form woven bone and then remodels to form secondary spongiosa. Metaphyseal corner fracture
Secondary spongiosa - Remodelling (Renal SUFE)
Groove of Ranvier - adds mechanical strength to physis and apppositional bone growth (supplies chondrocytes)
Perichondral ring LaCroix - anchors and supports physis peripherally