Cartilage

Cartilage is a type of dense connective tissue. Cartilage is composed of cells called chondrocytes which are dispersed in a firm gel-like ground substance, called the matrix. Cartilage contains no blood vessels and nutrients are diffused through the matrix. Cartilage is found in the joints, the rib cage, the ear, the nose, in the throat and between intervertebral disks. There are three main types of cartilage: hyaline, elastic and fibrocartilage.

Growth and development

Chondrification

Most of the skeletal system is derived from mesoderm tissue. Chondrification is the process in which cartilage is formed from condensed mesenchyme tissue, which differentiates into chondrocytes and begins secreting the materials that form the matrix.

Related Topics:
Skeletal - Mesoderm - Mesenchyme - Chondrocytes

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Mineralisation

Adult hyaline articular cartilage is progressively mineralised at the junction between cartilage and bone. It is then termed articular calcified cartilage. A mineralisation front advances through the base of the hyaline articular cartilage at a rate dependent on cartilage load and shear stress. Intermittent variations in the rate of advance and mineral deposition density of the mineralising front lead to multiple tidemarks in the articular calcified cartilage.

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Adult articular calcified cartilage is penetrated by vascular buds, and new bone produced in the vascular space in a process similar to endochondral ossification at the physis. A cement line demarcates articular calcified cartilage from subchondral bone.

Related Topics:
Endochondral ossification - Physis

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Two types of growth can occur in cartilage: appositional and interstitial.

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Appositional

Appositional growth results in the increase of the diameter or thickness of the cartilage. The new cells derive from the perichondrium and occur on the surface of the cartilage model.

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Interstitial

Interstitial growth results in an increase of cartilage mass and occurs from within. Chondrocytes undergo mitosis within their lacuna but remain imprisoned in the matrix, which results in clusters of cells called isogenous groups.

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