Understanding Connective Tissue Functions and Types

Sep 17, 2024

Connective Tissue Lecture Notes

Overview

  • Connective tissue is the most abundant tissue type in the body.
  • Functions include binding, support, protection, insulation, storage, and transportation of substances.
  • All connective tissues originate from embryonic tissue called mesenchyme.
  • Composed of cells and an extensive extracellular matrix.

Types of Connective Tissue

  1. Connective Tissue Proper
  2. Cartilage
  3. Bone
  4. Blood

Common Characteristics

  • All types are derived from mesenchyme.
  • Composed of cells and an extensive extracellular matrix.
  • Main components: ground substance, fibers, and cells.

Components of Connective Tissue

  1. Ground Substance
    • Fills space between cells and connects fibers.
    • Made of interstitial fluid, cell adhesion proteins, and proteoglycans.
  2. Fibers
    • Collagen Fibers: Strongest, made of collagen protein, stronger than steel.
    • Elastic Fibers: Made of elastin, stretchy, forms networks.
    • Reticular Fibers: Similar to collagen, forms networks.
  3. Cells
    • Immature cells called "blasts" secrete ground substance and fibers.
    • Mature cells end in "cyte".
    • Different types include fibroblasts/fibrocytes, chondroblasts/chondrocytes, osteoblasts/osteocytes.

Types of Connective Tissue

1. Connective Tissue Proper

  • Loose Connective Tissue
    • Areolar: Supports/binds tissues, stores fluid.
    • Adipose: Contains fat cells, stores nutrients, insulates.
    • Reticular: Supports structures with reticular fibers.
  • Dense Connective Tissue
    • Regular: Collagen fibers in parallel, forms tendons/ligaments.
    • Irregular: Collagen fibers in different directions, resists multi-directional tension.
    • Elastic: More elastic fibers, allows for stretch.

2. Cartilage

  • Withstands tension and compression, lacks nerves and blood vessels.
  • Hyaline Cartilage: Most abundant, cushions and supports.
  • Elastic Cartilage: More elastic fibers, found in ear.
  • Fibrocartilage: Rows of chondrocytes and collagen, compressible, found in spinal discs.

3. Bone (Osseous Tissue)

  • Harder than cartilage, contains collagen and inorganic calcium salts.
  • Contains blood vessels unlike cartilage.

4. Blood

  • Considered connective tissue as it develops from mesenchyme.
  • Blood cells in nonliving fluid matrix called plasma.

Note on Other Tissue Types

  • Muscle and nervous tissue will be discussed in context with their respective systems later in the course.