from the articular surface down , the condyle may be divided into five layers made up of cells embedded in a matrix : 1 ) the articular layer composed of static cells in a matrix rich in fibers presumed to be of type i collagen , 2 ) the polymorphic cell layer including the progenitor cells from which arise the cells undergoing endochondral changes , 3 ) the flattened cell layer in which cells produce a precartilagenous matrix devoid of type ii collagen while undergoing differentiation in two stages : a `` '' chondroblast '' '' stage and a short `` '' flattened chondrocyte '' '' stage when intracellular type ii collagen elaboration begins , 4 ) the upper hypertrophic cell layer , in which cells are `` '' typical chondrocytes '' '' that enlarge at a rapid rate , actively produce type ii collagen , and deposit it into a cartilagenous matrix , and 5 ) the lower hypertrophic cell layer , composed of chondrocytes at a stage of terminal enlargement while the cartilagenous matrix is adapting for mineralization .
C0007589
differentiation
C0007634
ophi