How Do Epithelial Tissues Contribute to Barrier Function?
Epithelial tissues exhibit a variety of specializations that enable their barrier function. The key elements include:
1. Tight Junctions: These are specialized connections between adjacent epithelial cells that prevent the passage of molecules and ions through the space between cells. Tight junctions are critical for creating a selective barrier, allowing the epithelial layers to control the flow of substances.
2. Adherent Junctions and Desmosomes: These structures provide mechanical stability by linking the cytoskeletons of adjacent cells. This physical integrity ensures that the epithelial layer remains intact and functional under various stress conditions.
3. Basement Membrane: This thin layer of extracellular matrix underlies the epithelial cells, providing support and anchoring them to underlying tissues. The basement membrane also plays a role in regulating the movement of cells and molecules.
