Lecture 11: Tissue Architecture Flashcards
1
Q
Cytoskeleton characteristics (single vs multiple protofilaments)
A
- DYNAMIC and ADAPTABLE
- rapid assembly and disassembly of cytoskeletal filaments
- filaments in sheets are thermally stable compared to single protofilament strands
- intermediate filaments are resistant to stretching forces
2
Q
What are the three types of cytoskeletal filaments?
A
- Intermediate filaments
- Microtubules
- Microfilaments
3
Q
Intermediate Filament characteristics
A
- high tensile strength (withstand mechanical stress)
- in cytoplasm –> network throughout cytoplasm (around nucleus, extends to periphery)
- forms NUCLEAR LAMINA (under nuclear envelope)
- coiled-coil filaments (good tensile strength)
4
Q
Microtubule characteristics
A
- organizational role in eukaryotic cells (CENTROSOME to periphery = tracks for transport)
- long, stiff hollow tubes
- mitotic spindle, flagella, cilia
- beta/alpha heterodimers (grow from + end = beta)
5
Q
y-tubulin
A
- located on the centrosome
- binds (-) end of microtubules and acts as an anchor for their growth
6
Q
Drugs that affects Microtubules (5)
A
- Taxol –> binds and stabilizes = no growth/breakdown
- Colchicine, Colcemid –> binds dimers = NO POLY.
- Vinblastine, Vinecristine –> bind dimers = NO POLY.
7
Q
Microfilament characteristics
A
- actin filaments (F-actin) –> grow from (+) end
- many unstable –> associated w/other proteins for stability
- essential for CELL MOVEMENT (locomotion, phagocytosis, division, contraction, etc)
8
Q
Drugs that affects Actin Filaments (3)
A
- Phalloidin –> binds/stabilize filaments (stall)
- Cytochalasin –> caps (+) end of filament (no growth)
- Latrunculin –> binds monomers = no polymerization
9
Q
What is collagen?
A
- main structural protein in ECM/connective tissue/basal lamina
- trimeric proteins (fibers, sheets, collagenous triple helix)
10
Q
What is the Extracellular Matrix?
A
- composed of intracellularly secreted fibrous proteins that aggregate
- interacts w/cells and tissues via transmembrane proteins (anchors cells together)
11
Q
What is the cause of Scurvy and what does it lead to?
A
- loss of ASCORBATE or IRON (cofactors)
- leads to improper or discontinued collagen production
- wounds re-open, body falls apart, teeth fall out, pale skin, sunken eyes
12
Q
What is the cause of Ehlers-Danlos Syndrome and what does it lead to?
A
- mutation in collagen or collagen synthesis genes (fibrous proteins and enzymes)
- alters production, structure, or processing of proteins interacting with collagen
- weakened CT in skin, bones, blood vessels, organs (hyperstretchy skin)
13
Q
What are the 4 major families of CAMs?
A
- Cadherins
- Ig-Superfamily
- Integrins
- Selectins
14
Q
Cadherins (E, N, VE, LI)
A
- calcium-dependent adhesion (junctions between cells)
- interact with actin
- demosomes and adheren junctions (homophilic)
E - epithelial
N - neural
VE - vascular endothelial
LI - liver-intestine
15
Q
EMT and Cadherin Switching
A
- markers for invasive, metastatic tumors
Epithelia to Mesenchymal Transition
- transitional bladder cancer
- dec. E cadherin, inc. N cadherin (more invasive)
