Cartilage

Cartilage is a rigid connective tissue, softer than bone but stiffer than muscle tissue. The cells composing cartilage are called chondrocytes, which produce large amounts of extracellular matrix proteins, such as collagen and elastin. There are three types of cartilage, elastic cartilage, hyaline cartilage and fibrocartilage- all with different properties and compositions of collagen and proteoglycans.

Cartilage is found at different locations in the body. In the respiratory system, cartilage is responsible of holding tubes open in the body, see trachea of the upper respiratory tract. Cartilage also functions as rubber-like padding at the end of bone, for example at the joints. It also has a structural purpose in the nose and ear. Elastic cartilage is found in the ear, while hyaline cartilage is found in the nose, larynx, trachea, bronchi and at the end of the bone of ribs and knee joint.

There are no nerves or blood vessels in cartilage, nutrition is supplied via diffusion to the chondrocytes.