Cartilage I

Histology 2016-2017
Department of Anatomy &Histology: Dr.Rajaa Ali
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CARTILAGE
Cartilage is a fi rm and fl exible type of scleral connective tissue in which the extracellular matrix has a fi rm consistency.

GENERAL FEATURES
_ Cartilage supports regions of the body that require varying degrees of fl exibility.
_ It is an avascular structure nourished by diffusion (lives anaerobically by glycolysis).
_ No nerves are present (insensitive) in cartilage.
_ Regeneration of cartilage is poor. Its damage results in a connective tissue scar.
_ It is covered externally by a dense connective tissue sheath known as perichondrium, except over articular surface of cartilage in the joint cavities and over fi brocartilage (Fig. ).
_ Perichondrium is made up of two layers:
1. Outer fi brous layer (vascular).
2. Inner chondrogenic layer (cellular).
_ Growth of the cartilage takes place by two mechanisms, viz.,
1. Appositional growth: Differentiation and multiplication of chondrogenic cells in the perichondrium into chondroblast.
2. Interstitial growth: Multiplication of deeply placed chondrocytes (daughter cells so formed remain in clusters called isogenous groups).
_ Growth of the cartilage depends mainly on the growth hormone which acts indirectly on it through somatomedin C produced in the liver.