In the 5th week of development the cartilage is seen as condensation of mesenchymal tissue in those regions where development of cartilage is required. The mesenchymal cells proliferate and assume a roughly round shape. At the same time collagenous or elastic fibers are deposited in the intercellular substance (which is now called matrix). Depending mainly on the nature of the matrix, three varieties of cartilage are formed: hyaline cartilage, fibrocartilage (both of which have collagenous fibers in the matrix), and elastic cartilage (which contains elastic fibers in its matrix).