Cartilage is made up of semi-hard and elastic material called chondrin. Its matrix is composed of proteins called chondromucoid and chondralbunoid. Chondromucoid and chondralbuinoid together are called chondrin. It contains collagen, elastin, proteoglycan, chondrocytes etc. Cartilage cells are called chondrocytes. Clusters of chondrocytes are called lacunae. It is covered by perichondrium.