CH.3 Compartmentation of Cells and Tissues

  1. Plasma Membrane
    (cell membrane)
    • separates body's major fluid compartments (extracellular and intracellular)
    • passive envelope
  2. Cytoplasm
    intracellular fluid packed with organelles
  3. Organelles
    small structures that perform specific cell functions
  4. Nucleus
    • controls cellular activities
    • lies near the center of the cell
  5. Intracellular Fluid (ICF)
    fluid within cells
  6. Extracellular Fluid (ECF)
    fluid outside cells
  7. Fluid Mosaic Model
    depicts the plasma membrane composed of a double layer (bilayer) of lipid molecules with protein molecules dispersed in it
  8. Lipid Bilayer
    • forms basic fabric of membrane
    • contructed of phospholipids
  9. Phospholipids
    each phospholipid has a polar head that is hydrophilic (charged) and a nonpolar tail that is hydrophobic (uncharged)
  10. Lipid Rafts
    • dynamic assemblies of saturated phospholipids (which pack together tightly) associated with unique lipids (sphingolipids and cholesterol)
    • assumed to be concentrating platforms for certain receptor molecules or for molecules needed for signaling  
  11. Integral Proteins
    (transmembrane proteins)
    • firmly inserted into the lipid bilayer
    • some are enzymes
    • most transmembrane proteins are involved in transport, clustering together to form channels (or pores)  which water-soluable molecules or ions can move through (bypassing the lipid part of the membrane)
    • others act as carriers that bind to a substance and moves it through the membrane
    • others are receptors for hormones or other chemical messengers and relay messages to the cell interior (a process called signal transduction)
  12. Peripheral Proteins
    • attach loosely only to integral proteins and are easily removed
    • some are enzymes
    • others are motor proteins involved in mechanical functions (i.e. cell shape during cell division, muscle cell contraction)
  13. Cytoskeleton
    peripheral proteins restricted in their movement due to being "tethered" to intracellular structures that make up the cytoskeleton
  14. Glycocalyx
    • "sugar covering" (sugar coated cells ;p)
    • describes the fuzzy, sticky, carbohydrate-rich
    • area at the cell surface
    • glycocalyx clings to each cell's surface thats enriched with glycolipids and glycoproteins (secreted by the cell)
    • provides highly specific biological markers by which approaching cells recognize each other (ex: a sperm recognizes an ovum by the ovum's unique glycocalyx; cells of the immune system identify bacterium by binding to certain membrane glycoproteins in the bacterial glycocalyx)
  15. Tight Junction
    • a series of integral protein molecules in the plasma membranes of adjacent cells fuse together, forming an impermeable junction that encircles the cell
    • helps prevent molecules from passing through the extracellular space between adjacent cells
  16. Desmosomes
    • anchoring junctions bind adjacent cells together and help form an internal tension-reducing network of fibers
    • abundant in tissues subject to great mechanical stress (i.e. skin, heart)
  17. Gap Junctions
Card Set
CH.3 Compartmentation of Cells and Tissues
cell and tissue physiology