Cartilage

Question 1

3 Types of Cartilage on LM

Answer 1

Hyaline -PERICHONDRIUM; fibers not visible in LM but look for dark proteoglycans

Elastic-PERICHONDRIUM; stain elastin w/ Orcein or Verhoeffs

Fibrocartilage-NO PERICHONDRIUM (blends into surrounding tissue); look for long fibers in LM

Question 2

2 Types of Growth

Answer 2

1- appositional growth or growth on edge of existing cartilage

2- interstitial growth or growth w/in tissue itself; form isogenous groups as they divide

Question 3

Perichondrium (2 layers)

Answer 3

• connective tissue sheath surrounding cartilage
• 1- Fibrous Layer - outermost; dense irregular connective tissue; integrity and protection
• 2- Chondrogenic Layer - just inside the fibrous layer; contains cells w/ potential to become new chondroblasts (appositional growth or growth on edge of existing cartilage)

Question 4

Cartilage Cells

Answer 4

• Chondroblasts - produce cartilage matrix
• Chondrocytes - mature cartilage cells that are now trapped in matrix (lacuna are pockets of trapped chondrocytes)
  - Capable of mitotic divisions –> form isogenous groups as they divide (interstitial growth or growth w/in tissue itself)

Question 5

Cartilage Matrix

Answer 5

• Hallmark = type II collagen
• Elastin (mainly in elastic cartilage)
• Ground substance
  
  • Aggregcan- large proteoglycan w/ 3 layers of branching so carries a lot of water
    
    • Proteoglycan are negatively charged so stain dark; they are concentrated immediately around lacunae - formed territorial matrix
• specialized glycoproteins…
• 1- Chondronectin - LINKER - links cartilage cells to matrix
• 2- Chondronectin - Ca++ binder; important for calcification of hyaline cartilage during bone formation