Hyaline cartilage is a type of connective tissue which is typically flexible and whitish-blue in color. Generally found in the nose, larynx, wind pipe, and bronchial tubes leading to the lungs, it is made up of mostly a gel-like substance called collagen and a fibrous structure, or matrix, which normally encloses the biological cells. This matrix is mostly composed of proteins and water. Usually the function of hyaline cartilage enables it to withstand both pulling and compressive forces from bone movement.
The function of hyaline cartilage is also normally to support the movable joints between bones, as well as the connections between the ribs and the breast bone, or sternum. Usually supporting the physical structure of an embryo before bones form, the cartilage is also normally where bones grow in length. Like other types of cartilage, it does not usually regenerate, or repair, as quickly as other tissues. There are no blood vessels passing through, so the cartilage typically relies on nutrients and oxygen that diffuse out of other tissues.
Cells called chondrocytes typically contribute to the functioning of hyaline cartilage, and can secrete fibers and other substances that are part of the material in between them. Spaces between the cells, called lacunae, develop as the surrounding matrix grows. The chondrocytes can develop by adding to the components of the cartilage, secreting certain necessary compounds. They can also undergo growth in which cellular division called mitosis takes place inside the cartilage.
Another layer of connective tissue, called a perichondrium, normally helps support the function of hyaline cartilage. A layer of fibers and a layer of cells are usually located within this structure. These cells divide and also differentiate as they form within the perichondrium, which is also usually where cartilage grows. When hyaline cartilage is damaged, chondrocytes can turn into other types of cells, called chondroblasts, which can deposit materials on the surface that get added to the overall structure.
Other types of cartilage include elastic, which typically has dense fibers and abundant collagen. Elastic cartilage is often found in the larynx, outer part of the ear, inside the auditory canal, and in the eustachian tube between the middle ear and the throat. The living cells in fibrocartilage are usually located in between dense collagen fibers. This kind of cartilage is usually found in between spinal discs, in the knee, and where tendons and ligaments connect to bone. It normally works similar to the function of hyaline cartilage, which is generally the most common type in the body.