Flashcards in Interactions between cells and their environments: Part 1 Deck (45):
Cells are organized into _______
What gets transmitted from cell to cell by cytoskeletal filaments?
What makes up epithelial tissues?
lines, cavities, organs and surfaces
What are examples of connective tissues?
Compare epithelial tissues and connective tissues based on cell association, the amount of ECM, what provides resistance to mechanical stress, and what cells are attached to.
Epithelial tissues: cells closely associated; limited ECM; cytoskeletal filaments provide resistance to mechanical stress; cells are attached to each other
Connective tissues: cells rarely connected; lots of ECM; ECM provides resistance to mechanical stress; cells attached to the matrix
What is the basal lamina?
thin layer of ECM
What are four types of junctions? Which ones are present in epithelial cells?
1. anchoring junctions
2. channel-forming junctions
3. occluding junctions
4. signal-relaying junctions
What is another name for occluding junctions? What are two functions
1. creates a tight seal between cells to prevent mixing of the extracellular environment
2. act as fences in the membrane to prevent mixing of membrane proteins (apical and basal)
______ and ______ proteins form the seal.
claudin and occludin
What interacts with extracellular domains of the proteins in one cell?
extracellular domains of the neighbouring cell
Claudin is required for...
tight junction seals
What is a sealing strand?
many tight junctions
Plasma membranes of ______ cells are brought closer together at the sealing strand
Tight junctions are dependent on ______ junctions.
What happens if you block the formation of adherens junctions?
tight junctions don't form properly
What three junctions make up the junctional complex
tight junctions, adherens junctions, desmosomal junctions
Where are anchoring junctions located?
Anchoring junctions link the ______ of neighbouring cells.
What do adhesion and anchor proteins link together?
cytoskeletons of neighbouring cells
What two things do adhesion proteins interact with?
1. neighbour adhesion proteins
2. anchor proteins
What is an example of adhesion proteins?
What links the adhesion proteins to cytoskeletal filaments? (cytosolic proteins)
What does the adhesion belt encircle?
the inside of the PM
What kind of proteins are adhesion and anchor proteins? (location)
adhesion: transmembrane proteins
anchor: cytosolic proteins
What is tethered to cadherin by anchor proteins
What two things link intermediate filaments?
desmosomes and hemidesmosomes
What is the function of intermediate filaments?
provide structural support
What does a desmosome link to?
What does a hemidesmosome link to?
What are two specific cadherin family adhesion proteins?
desmoglein and desmocollin
Hemidesmosomes link to _____ filaments inside the cell and link to _____ in the ECM
What is integrin?
a transmembrane protein in hemidesmosome; links anchoring proteins to laminin
Where is laminin located?
Hemidesmosomes anchor _______ _______ in a cell to the ECM
What is the role of gap junctions? What are they composed of?
provide communication between cells; composed of connexin proteins
1 connexin = 4 ?
6 connexins = 1 ?
4 transmembrane proteins
2 connexons = 1 ?
What is another term for connexon?
Different connexin proteins can be present in the same ______
What are two types of connexons? What are two types of intercellular channels?
Gap junctions allow the passage of ______ and ______.
ions and metabolites
Are gap junctions gated?
yes; can be in open or closed state
Is one connexon on its own usually open or closed?
A dramatic increase in _____ _____ will close jap junctions.
Is cytosolic calcium usually low or high?