Lecture Notes: Epithelial and Connective Tissues

Overview

• Epithelial Tissue

  • Forms the outer surface of the body.
  • Contains a high density of cells.

• Connective Tissue

  • Lies beneath the epithelial tissue.
  • Composed of fewer cells and a lot of fibers.
  • Provides structure and support, maintaining tissue integrity.

• Basement Membrane/Basal Lamina

  • Separates epithelial tissue from connective tissue.

Detailed Structure

• Fibers

  • Integral to maintaining the tightness and integrity of tissues like skin and gums.
  • Inflammation can lead to fiber breakage, causing puffiness.

• Rete Ridges and Connective Tissue Papillae

  • Rete Ridges: Downward projections of the epithelial tissue.
  • Connective Tissue Papillae: Upward projections of the connective tissue.

Connective Tissue

• Also known as Lamina Propria.
• Characterized by fewer cells but abundant fibers.
• Contains blood supply.

Cell Junctions

Desmosomes

• Function: Connect two neighboring epithelial cells.
• Analogy: Snaps like a denim jacket.

Hemidesmosomes

• Function: Connect cells to the basal lamina.
• Structure: Half of a desmosome.
• Ensures cells are anchored to the connective tissue via the basal lamina.

Summary

• Epithelial and connective tissues are distinct but interconnected via the basement membrane.
• Fibers in connective tissue provide essential structural support.
• Cell junctions like desmosomes and hemidesmosomes play critical roles in maintaining tissue integrity and attachment.