Extracellular Structures

Nota:

• Plants, fungi, prokaryotes (some protists) only! Keeps it @ happy medium concerning water uptake, Protection:

1. Cellulose

   Nota:

   • Makes up cell wall; Dotted with polysaccharides and proteins
2. Primary Cell Wall

   Nota:

   • Thin and flexible, 
   1. Middle Lamella

      Nota:

      • In-between layer, Main wall between cell's cell neighbors.
      1. Secondary Cell Wall

         Nota:

         • Not all cells have this! Added layer between plasma membrane and primary cell wall
3. Plasmodesmata

   Nota:

   • "Streets" for cell's neighborhood of cells

Nota:

• Animal cells only!

1. Glycoproteins

   Nota:

   • Collagen, proteoglycans, and fibronectin.
2. Function

   Nota:

   • Support Adhesion Movement Regulation Communication for cells
3. Intercellular Junctions
   1. Plasmodesmata

      Nota:

      • Tunnels going through hard plant cell walls
      • Allows for solutes, water, proteins and RNA to get from cell to cell.
      • Keeps things inside and things outside ; prevents organisms from going "spetic".
   2. Tight Junctions

      Nota:

      • Cells are touching each other this point! Keeps them from leakaging extracellular "slime" 
      1. Blood-brain barrier
      2. Epithelia (intestine)
   3. Desmosomes

      Nota:

      • Sheet-shaped fasteners that keeps cells together
      • Aka. anchoring junctions
      1. Cardiovascular tissue
   4. Gap Junctions

      Nota:

      • Tunnels for cytoplasm to get to neighboring cells
      • Aka. communicating junctions
      • import --> regulates what is going in and out; can open and close; helps to take in + expel waste
      1. Skeletal muscle
   5. Function

      Nota:

      • To make physical contact with other cells in tissues, organs or organ systems in communication.