Overview of Connective Tissue

Introduction

• Connective tissue is one of the four primary tissue types, alongside epithelial, nervous, and muscular.
• Unique for being varied and widely distributed throughout the body.

Unique Characteristics

• Variety and Distribution: Includes blood (fluid, fills vessels/heart) and bone (solid, structural support).
• Locations: Found in skeletons, dermis, tendons, ligaments.

Matrix

• Abundant in connective tissue.
• Composed of extracellular material.

Vascularization

• Varies among types; can be well-vascularized, poorly, or avascular.

Origin

• All connective tissues originate from mesoderm in embryonic development, giving rise to mesenchyme.

Types

1. Fluid Connective Tissue: Includes blood and lymph.
2. Fibrous Connective Tissue: Includes fat, tendons, and ligaments.
3. Supportive Connective Tissue: Includes cartilage and bone.

Components of Connective Tissue

• Cellular Components:
  • Immature Cells: End in "-blasts" (e.g., osteoblasts, chondroblasts), responsible for matrix creation.
  • Mature Cells: End in "-cytes" (e.g., osteocytes, chondrocytes), maintain the matrix.
  • Other Cells: Include macrophages, neutrophils, mast cells (produce histamine), plasma cells (produce antibodies), and adipocytes (store lipids).

Matrix Components

• Ground Substance: Varies in texture (fluid, viscous, rubbery, calcified).
  • Glycosaminoglycans (GAGs): Provide support, hold electrolytes and water.
  • Proteoglycans: Attach cells to each other and to the matrix.
  • Adhesive Proteins: Serve as glue for cells and matrix.

Fibers

1. Collagen Fibers: Provide tensile strength; found in tendons, ligaments, dermis.
2. Reticular Fibers: Thin, branching; create frameworks/stromas in lymphatic organs.
3. Elastic Fibers: Allow elasticity; found in lungs, arteries, dermis.

Summary

• Discussed unique characteristics of connective tissues.
• Types and roles of cells: immature "-blasts" and mature "-cytes".
• Components of the matrix: ground substance and fibers.