1. Cell Junctions
Section 5.7

2. Learning Objectives
Compare the structures and functions of anchoring junctions, tight junctions, gap junctions, and plasmodesmata

3. Cell Junctions
Cell junction = Structure that connects a cell to other cells
Aid in cellular communication
Help cells stick together to make tissues
Prevent the passage of materials
4 main types
Anchoring junctions
Tight junctions
Gap Junctions
Plasmodesmata

4. Anchoring Junctions Found in animal cells 2 Functions:
Locks cells together
Found in large number in skin & tissues that experience scratching or stretching
Strengthen tissues that contract
Ex. Found in heart muscle
Connect cytoskeleton filaments inside the cell to the ECM on the outside of the cell
Allows messages from the outside environment to be received

5. Desmosomes
Adhering Junctions

6. Tight Junctions Found in animal cells
Prevent body fluids from leaking between neighboring cells
Ex. Lining of your stomach is covered in tight junctions to keep stomach acid in your stomach
Found in tissues that line body surfaces or form internal cavities

7. Gap Junctions Found in animal cells
Make channels that connect the cytoplasm of neighboring cells
Similar to plasmodesmata
Can open or close in response to a stimulus (aid in communication)
Found in cells that perform coordinated actions
Ex. Heart muscle

8. Plasmodesmata Found in plant cells
Open channels (tubes) that go through the cell walls
Connects the cytoplasm of adjoining cells
Similar to gap junctions in animal cells