CARTILAGE

Cartilage

1. Classify cartilages

Cartilages are classified into three main types based on their microscopic structure and function:

• Hyaline cartilage (90% of cartilage in the human body)
• Fibrocartilage (5% of cartilage in the human body)
• Elastic cartilage (5% of cartilage in the human body)

2. Describe the microscopic structure of hyaline cartilage

Hyaline cartilage:

• Matrix: Homogeneous, eosinophilic, and glassy appearance with thin collagen fibers
• Cells: Chondrocytes (round or oval in shape with central nucleus)
• Perichondrium: Present in some parts (outer layer of dense connective tissue)
• Collagen fibers: Thin and randomly arranged
• Proteoglycans: High concentration of proteoglycans such as aggrecan

3. Describe the microscopic structure of fibrocartilage

Fibrocartilage:

• Matrix: Dense and highly organized collagen fibers with sparse chondrocytes
• Cells: Chondrocytes (spindle-shaped with central nucleus)
• Perichondrium: Absent
• Collagen fibers: Thick and highly organized (in the form of fibers)
• Proteoglycans: Low concentration of proteoglycans
• Composed of type I and type II collagen fibers

4. Describe the microscopic structure of elastic cartilage

Elastic cartilage:

• Matrix: Presence of elastic fibers with sparse chondrocytes
• Cells: Chondrocytes (round or oval in shape with central nucleus)
• Perichondrium: Present
• Collagen fibers: Thin and randomly arranged
• Proteoglycans: Low concentration of proteoglycans
• Composed of type II and type I collagen fibers with elastic fibers

Diagram of cartilage types

Hyaline cartilage | |--Matrix (homogeneous) |--Cells (chondrocytes) |--Perichondrium (present in some parts) | |--Collagen fibers (thin) |--Proteoglycans (high concentration)

Fibrocartilage | |--Matrix (dense and highly organized) |--Cells (chondrocytes) |--Perichondrium (absent) | |--Collagen fibers (thick and highly organized) |--Proteoglycans (low concentration)

Elastic cartilage | |--Matrix (presence of elastic fibers) |--Cells (chondrocytes) |--Perichondrium (present) | |--Collagen fibers (thin and randomly arranged) |--Proteoglycans (low concentration)