1. Intercellular Junctions

2. In Plants Plasmodesmata:
channels that perforate plant cell walls, through which cytoplasmic strands communicate between adjacent cells.
Allows free passage of water and small solutes.
Enhanced by cytoplasmic streaming

3. In Animals Tight Junctions:
Intercellular junctions that hold cells together tightly enough to block transport of substances through the intercellular space
Specilaized membrane proteins in adjacent cells bond directly to each other allowing no space between memebranes

4. In Animals Desmososmes:
Rivet cells together into strong sheets, but still permit substances to pass freely through intercellular spaces
Made of a dense disk inside plasma membrane that is reinforced by intermediate filaments of keratin

5. In Animals Gap junctions
Specialized for material transport between cytoplasm of adjacent cells
Common in animal embryos and cardiac muscle where chemical communication between cells is essential