Chapter 19: Cell Junctions and the Extracellular Matrix

Tight Junctions

Specialized structures that form a seal between adjacent cells, preventing the passage of molecules and ions between the cells.

Adherens Junctions

Structures involved in cell-cell adhesion and provide mechanical strength to tissues.

Desmosomes

Strong intercellular junctions that provide mechanical stability and resistance to shearing forces.

Gap Junctions

Specialized channels that allow direct communication and exchange of small molecules between adjacent cells.

Hemidesmosomes

Specialized junctions that anchor epithelial cells to the underlying extracellular matrix, providing stability and mechanical support.

Extracellular Matrix (ECM)

Complex and dynamic network of macromolecules found in the extracellular space of animal tissues, providing structural support and biochemical cues to cells.

Focal Adhesions

Large, dynamic structures that connect the extracellular matrix to the actin cytoskeleton within cells, transmitting mechanical forces and regulating cell adhesion strength.

Podosomes

Dynamic, actin-rich structures found in specialized cells like osteoclasts and macrophages, functioning as sites of cell adhesion, extracellular matrix degradation, and cell migration.

Plant Cell Wall

Complex and rigid structure that surrounds the plasma membrane of plant cells, providing structural support, mechanical strength, and protection.

Plasmodesmata

Specialized regions in the plant cell wall that are channels connecting adjacent cells, allowing the exchange of molecules and signaling between cells.