structure of cartilage

• contains numerous fibres made of protein called collagen which gives it a certain amount of flexibility
• fibres are embedded in a firm matrix of protein-carbohydrate complex called chondrin which allows the cartilage to function as a structural support. within are spaces containing cartilage cells called chondroblasts. they produce matrix and gradually become surrounded by it until they are trapped in small spaces called lacunae. the cells are considered mature when this happens and are called chondrocytes
• types of cartilage : hyaline cartilage, elastic cartilage, fibrocartilage
• hyaline cartilage contains many closely packed collagenous fibres throughout its matrix. they give the cartilage strength and flexibility and are so fine that they are not distinguishable under a light microscope.
• hyaline cartilage makes up the rings of trachea and bronchi and are also found in articular cartilage at the ends of bones, where two bones meet to form a joint
• elastic cartilage contains conspicuous elastic fibres and collagenous fibres similar to the ones in hyaline cartilage, but not so closely packed
• elastic cartilage provides flexible elastic support in places like the external ear
• fibrocartilage contains parallel bundles of thick collagenous fibres which give it a course appearance. the fibres are not compact which allow it to be compressed slightly
• fibrocartilage is ideal for regions where the weight of the body is being supported or places that need to withstand heavy pressure. it is found in the intervertebral discs of the spinal column, providing a cushion between vertebrae. it is also found in the meniscus of knee joints and tissue joining two sides of the pelvis
• cartilage does not contain blood vessels, all nutrients and waste removal depends on diffusion through the matrix. this is a slow process resulting in chondrocytes having a slow rate of metabolism and cell division, therefore, injured cartilage takes longer to heal.
• the blood supply comes from blood vessel in it inner layer of perichondrium. this is a fibrous membrane of connective tissue that covers the external surface of cartilage. except where cartilage forms articular surface of a joint