Characteristic Features of Cartilage in Animals

The cartilage is a supportive tissue in the animal body. Cartilage is specialized for a supportive role possesses considerable tensile strength which provides weight bearing ability, movement and organ integrity. It is composed of amorphous gel like matrix, and cells. The matrix is composed of collagenous fibres (mainly type II but type I predominant in fibro-cartilage) and the firm but pliable ground substance. Biochemically, ground substance has high content of glycosaminoglycans (GAGs) and also keratan sulfate, hyaluronic acid etc. This framework of matrix provides high tensile strength of cartilage and also binding ability to water results increase in elasticity and plasticity. These qualities of cartilage provide its roles in cushioning, movement and support. The two types of cells viz., chondroblasts and chondrocytes are recognized in cartilage. The chondroblasts are actively dividing cells that forms matrix of cartilage. These cells are found in the inner chondrogenic layer of perichondrium. After complete matrix formation chondroblast become less active cells, chondrocytes. Each chondrocyte is located within a lacuna and distributed throughout the matrix. The cartilage is avascular, aneural and alymphatic in character. The nutrients supply to cartilage cells depends upon diffusion through matrix. The nutrient diffuse from nearby capillaries located in the perichondrium and in the articular cartilage supplied from synovial fluid. The process of cartilage repair is limited due to its avascular nature and low metabolic activity of chondrocytes. Clinical or surgical management techniques can enhance cartilage repair.