Types of Cell Junctions
Cards (10)
- Desmosomes:
- Similar in structure to adherence junctions
- Intermediate filaments extend into the cytosol of each cell
- Provide stability to tissues
- Abundantly found in the epidermis of the skin and between muscle cells of the heart
- Hemi-Desmosomes:
- Provide strong attachments between cells and other extracellular materials like the basement membrane of epithelial tissues
- Most abundant in tissues subjected to constant frictional or abrasive forces
- Gap Junctions:
- Open communication channels
- Transmembrane proteins called connexins join to create tiny tunnels forming gaps between adjacent membranes
- Allow ions and small molecules to pass freely from one cell to another
- Allow rapid passage of electrical impulses between cells
- Particularly abundant in some types of muscle tissue
- Cells of many tissues are joined together by intercellular junctions located between adjacent cells
- Types of intercellular junctions:
- Tight junctions
- Adherence junctions
- Desmosomes
- Hemidesmosomes
- Gap junctions
- Tight junctions:
- Found in tissues lining the surface of organs and body cavities like the stomach, intestines, and urinary bladder
- Fuse the plasma membranes of adjacent cells together to restrict the movement of substances like hydrochloric acid
- Adherence junctions:
- Created when transmembrane proteins anchored to a dense plaque of proteins inside the cell connect the adjacent cell membranes together
- Microfilaments extend from the plaque into the cytosol of each cell to help resist separation of epithelial tissues
- Desmosomes:
- Provide strong adhesion between cells
- Common in tissues like epithelium and some types of muscular and nervous tissue
- Hemidesmosomes:
- Half desmosomes that anchor cells to the basement membrane
- Help in maintaining the structural integrity of tissues
- Gap junctions:
- Areas where the plasma membranes of adjacent cells are fused together
- Allow for communication and passage of small molecules between cells