Cartilage: Structure, Function, and Considerations

Cartilage is a specialized type of connective tissue known for its high elasticity and ability to withstand significant forces. It lacks blood vessels and nerves, making repair and regeneration of cartilage very slow.

1. Structure of Cartilage:

• Cartilage Cells:

• Chondroblasts: These are immature cells with the ability to divide and produce cartilage matrix. They are round, have large nuclei, and their cytoplasm contains abundant ribosomes and rough endoplasmic reticulum.

• Chondrocytes: These are mature cells that reside in spaces within the matrix called lacunae. They are typically round or oval, have smaller nuclei, and their cytoplasm contains fewer ribosomes and more smooth endoplasmic reticulum.

• Cartilage Matrix:

• This is the extracellular substance that surrounds the cartilage cells and is composed of various organic components and water.

• The primary components of the matrix are collagen, chondroitin sulfate, and water.

• The most prevalent type of collagen in cartilage is collagen type II, which forms the fibrous network of the matrix.

• Fibrocartilage, in addition to collagen type II, also contains collagen type I.

2. Types of Cartilage:

There are three main types of cartilage:

• Hyaline Cartilage:

• The most common type of cartilage.

• Has a clear, homogeneous matrix with abundant collagen type II.

• Found in articular surfaces (joint surfaces), nasal cartilage, trachea, and laryngeal cartilage.

• Usually surrounded by a perichondrium (except for articular cartilage and epiphyseal cartilage).

• The cells responsible for hyaline cartilage are chondroblasts and chondrocytes.

• Elastic Cartilage:

• The matrix contains a high concentration of elastin fibers in addition to collagen type II.

• Exhibits high elasticity.

• Found in the external ear, auditory canal, and epiglottis.

• Usually surrounded by a perichondrium.

• The cells responsible for elastic cartilage are chondroblasts and chondrocytes.

• Fibrocartilage:

• The matrix is dense with thick collagen type I fibers and a lower proportion of collagen type II.

• Exhibits high tensile strength.

• Found in intervertebral discs, tendon attachments to bone, and some joint capsules.

• Lacks a perichondrium.

• The cells responsible for fibrocartilage are chondroblasts and fibroblasts.

3. Functions of Cartilage:

• Support and Shape: Cartilage provides structural support for the body, especially in regions requiring flexibility.

• Reduce Friction at Joints: Cartilage covers articular surfaces, minimizing friction during movement.

• Protect Underlying Tissues: Cartilage acts as a cushion, safeguarding underlying tissues from damage.

• Enable Flexible Movement: Cartilage contributes to the elasticity and flexibility of body parts.

4. Cartilage Regeneration:

• Due to the lack of blood vessels, cartilage has a limited ability to regenerate.

• The perichondrium (when present) can provide cells for cartilage repair.

• Cartilage cell proliferation and metabolism are influenced by growth hormone (GH).

5. Considerations:

• Cartilage is susceptible to damage from trauma, aging, and disease.

• Common cartilage-related disorders include osteoarthritis, rheumatoid arthritis, and developmental cartilage abnormalities.

• Protecting and maintaining cartilage health is essential:

• Maintain a balanced diet, including adequate collagen and chondroitin sulfate.

• Engage in regular, moderate exercise, avoiding strenuous activities.

• Keep a healthy weight.

Note: This information is intended for educational purposes only. Always consult with a doctor or healthcare professional for personalized advice and treatment.