Cartilage: It is a specialized connective tissue characterized by an extracellular matrix enriched with glycosaminoglycans & proteoglycans, macromolecules that interact with collagen and elastic fibres.
Origin: Cartilage develops from primitive mesenchyme cells.
- Cartilage develops from mesenchyme and consists of cells, called chondrocytes and an extensive extracellular matrix composed of fibers and ground substance.
- Cartilage is characterized by an extracellular matrix enriched with glycosaminoglycans and proteoglycans with collagen and elastic fibers.
- Chondrocytes synthesized and secrete the ECM and the cells themselves are located in matrix cavities called lacunae.
- Most cartilage is enveloped by a sheath of dense connective tissue called perichondrium.
- Cartilage lacks lymphatic vessels and nerves.
Components of cartilage: Cartilage consists of cells (chondrocytes) and an extensive extracellular matrix composed of fibers and ground substance.
Cell: Two types of cells are found:
- Chondroblasts and
Extracellular matrix: It is composed of
- Fibres: Collagen and elastic.
- Ground substance: It is composed of:
- Cartilage is involved in supporting the soft tissues of the body.
- It allows the tissue to bear mechanical stresses without permanent distortion.
- It is shock absorbing and sliding area for joints and facilitates bone movements.
- Cartilage is essential for the development and growth of long bones before and after birth.
Hyaline cartilage: It contains type-II collagen is matrix, is the most abundant cartilage in the body and serves many functions. Examples:
- Costal cartilage.
- Articular cartilage.
- Thyroid cartilage.
Fibrocartilage: It has a matrix containing a dens network of coarse type-I collagen fibres. Examples:
- Intervertebral disc.
- Symphysis of pubis.
- Menisci of knee joint.
Elastic cartilage: It contains type-II collagen & abundant elastic fibres scattered throughout its matrix, giving it more pliability. Examples:
- Auricle of external ear.
- Walls of external auditory canals.
- Auditory tubes.