Cartilage as the cricoid cartilage and carina. Cartilage is composed of specialized cells called chondrocytes that produce a large amount of collagenous extracellular matrix, abundant ground substance that is rich in proteoglycan and elastin fibers. Cartilage is classified in three types, "elastic cartilage", "hyaline cartilage" and "fibrocartilage", which differ in relative amounts of collagen and proteoglycan. Cartilage does not contain blood vessels (it is avascular) or nerves (it is aneural). Nutrition is supplied to the chondrocytes by diffusion. The compression of the articular cartilage or flexion of the elastic cartilage generates fluid flow, which assists diffusion of nutrients to the chondrocytes.
Hyaline cartilage cavities in the matrix, called cartilage lacunæ. These cavities are actually artificial gaps formed from the shrinking of the cells during the staining and setting of the tissue for examination. The inter-territorial space between the isogenous cell groups contains relatively more collagen fibres, allowing it to maintain its shape while the actual cells shrink, creating the lacunae. This constitutes the so-called 'capsule' of the space. Each lacuna is usually occupied by a single cell, but during mitosis, it may contain two, four, or even eight cells. Articular cartilage is hyaline cartilage on the articular surfaces of bones, and lies inside