Vet histology lecture #5

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Vet histology lecture #5
2013-09-16 00:10:48
Vet histology lecture

Vet histology lecture #5
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  1. What is meant by cell polarity?
    The cell has both an apical and basal membrane and these do not switch and can be quite different and unique
  2. name 3 intercellular (lateral) cell surface specializations, give some functions
    • Tight junctions - barrier
    • Adhering junctions - anchor
    • Communicating junctions - talking
  3. describe in detail tight junctions
    Found on membranes that are super close, essentially creates a super tight barrier that is impermeable
  4. 3 types of adhering junctions?
    • Intermediate junction - belt like
    • Desmonsomes - disk like
    • Hemidesmosomes - disk like
  5. What is anchored at adhering junctions?
    Cytoskeleton elements
  6. are intermediate junctions as tight as tight junctions? Where do you find them in relation to the tight junctions?
    • No but they have mechanical strength
    • Below the tight junctions
  7. WHat is the bonus of a desmosome?
    Gives flexibility as compared to intermediate junction
  8. What comes along with desmosomes? (used as anchor for other things)
    Attachment plaque which is used to anchor filaments
  9. What kind of cells would you expect to have lots of desmosomes?
    Cells that are often stretched or undergo mechanical stress often
  10. What is a hemidesmosome in comparison to a desmosome?
    • A half a desmosome, only on one side, so often seen on the basement membrane specifically
    • It helps connect to connective tissue
    • Also has aattachment plaque but obviously only on one side
  11. Purpose of gap junctions?
  12. What kind of cells would we expect to see a lot of gap junctions in?
    Cells that work together such as muscle cells`
  13. Through a gap junction a molecule is able to skip the ECM and go from?
    Cytosol to cytosol
  14. We can recognize gap junctions under a microscope cause it looks like?
    The membranes are super close and almost fused
  15. What size roughly can fit through gap junctions?
    Super small like no bigger than single amino acid
  16. What is a terminal bar?
    • Where the 2 membranes of the cell meet the lumen and cease to go in the same direction and splay off
    • Occurs where lateral surface meets apical surface
    • Essentially area of junctional complexes that cannot be distinguished
  17. Differnetiate between the function of cilia and the function of flagellum?
    • Cillia are to move things on their surface
    • Flagella move the actual cell itself
  18. Describe cilia motion as compared to the motion of a flagellum?
    • Cillia beat in one direction fold and reset
    • Flagella beat in a circle or in a concentric pattern to cause thrust
  19. Flagellum is made from what structure?
  20. what is an axoneme
    Microtunule based skeletonof cilia and flagella
  21. describe the inside of a cilia?
    2 central microtubules surrounded by 9 microtubules
  22. What is a microvilli?
    tiny tiny villi ontop of villi, they are essentially just membrane protrusions as compared to something that moves
  23. Why does each microvilli have cell membrane and glycocalyx on it?
    To hold digestive enzymes in for extra cellular digestion
  24. What is inside a microvilli often?
    Actin filaments
  25. What are stereocilia?
    Don't beat look like cilia but essentially very long microvilli for very specific purposes such as hearing
  26. What is the purpose of basal foldings?
    active ion movement