11. Tissue Architecture Flashcards
What are the 3 major components of the cytoskeleton?
Microfilaments:
- Actin (f-actin)
Microtubules:
- Tubulins
Intermediate filaments:
- Lamin
What are some of the purposes of the cytoskeleton?
Tissue Level:
- Muscle movement
Cellular Level:
- cell shape
- motility
- cell adhesion
- division
Sub-cellular Level:
- Organization
- Tensile Strength
- Chromosome segregation
- Cell polarity (top, bottom, side)
- Vesicular movement
What are the 4 important ways we can think of cytoskeletal elements?
- Dynamic
- Adaptable
- Stable
- Strong
Intermediate Filaments
- great tensile strength (rope like properties)
- found in cytoplasm
- often anchored to plasma membrane at cell-cell junctions
- form mesh-like structures called nuclear lamina
- cross-link filaments into bundles
- link to microtubules, actin filaments, and cell-junctions
What are the two classes of intermediate filaments?
Cytoplasmic:
- keratin filaments
- vimentin filaments
- neurofilaments
Nuclear:
- nuclear lamina, in all animal cells
What happens when there is faulty action of the nuclear lamina?
Increased cellular aging
Describe Microtubules
- long and stiff hollow tubes
- rapid assembly and disassembly
- create tracks to transport vesicles, organelles and other cell components
Describe the plus and minus ends of microtubules
(+): B-tubulin
- Growth
(-): a-tubulin
- Stability/Breakdown
What is the mechanism of action of Taxol?
binds and stabilizes microtubules
prevents cells from dividing and cells undergo apoptosis
What is the mechanism of action of Colchicine/Colcemid?
binds tubular dimers and prevents their polymerization
What is the mechanism of action of Vinblastine/Vincristine?
binds tubular dimers and prevents their polymerization
What is the function of y-tubulin?
y-tubulin forms a nucleus that attaches to the minus end and serves as an anchoring point from which to grow from
Describe Microfilaments
Actin filaments:
- twisted polymer of g-actin
- present in all cells
- essential for locomotion, phagocytosis, cell division, and contraction
What is the mechanism of action of Phalloidin?
binds and stabilizes actin filaments
What is the mechanism of action of Cytochalasin?
caps actin filament plus ends, preventing polymerization there