Lecture on Connective Tissue

Introduction

• Connective tissue: most abundant type of tissue.
• Functions: binding, support, protection, insulation, storage, transportation.
• Originates from embryonic tissue called mesenchyme.
• Composed of cells and extensive extracellular matrix.

Components of Connective Tissue

• Ground Substance
  • Fills space between cells, connects fibers.
  • Made of interstitial fluid, cell adhesion proteins, proteoglycans.
• Fibers
  • Collagen fibers: Strongest, made of collagen protein, stronger than steel.
  • Elastic fibers: Made of elastin, stretchy, form networks.
  • Reticular fibers: Support other tissues, form networks.
• Cells
  • Immature cells ("blast" suffix) secrete ground substance and fibers.
  • Mature cells ("cyte" suffix) include fibrocytes, chondrocytes, osteocytes.
  • Specialized cells: fat cells, others.

Types of Connective Tissue

Connective Tissue Proper

• Loose Connective Tissue
  • Areolar: Supports and binds tissues, stores fluid, most abundant.
  • Adipose: Fat cells, nutrient storage, insulation.
  • Reticular: Supports certain structures.
• Dense Connective Tissue
  • Regular: Collagen fibers resist tension, form tendons, ligaments.
  • Irregular: Collagen fibers in random arrangement.
  • Elastic: Elastic fibers, more flexibility.

Cartilage

• Withstands tension and compression.
• Lacks nerve cells and blood vessels, nutrients through diffusion.
• Types:
  • Hyaline: Most abundant, firm, cushions structures.
  • Elastic: Similar to hyaline, more elastic fibers, found in ear.
  • Fibrocartilage: Compressible, withstands tension, found in spinal discs.

Bone

• Harder than cartilage, contains blood vessels.
• Matrix includes collagen and calcium salts.
• Osseous tissue.

Blood

• Develops from mesenchyme.
• Cells surrounded by nonliving fluid matrix (blood plasma).

Conclusion

• Two more types of tissue (muscle and nervous) will be covered later.
• Next focus on other systems.