Cell Junctions

Question 1

Tight junctions

Answer 1

Web-like strands of transmembrane proteins
Fuse cells together
Seal off passageways between adjacent ce;;s
Key-word “leak-proof”
found in stomach, intestines and urinary bladder

Question 2

Adherens Junctions

Answer 2

Transmembrane glycoproteins called cadherins insert into the plaque and join cells
Plaque is a dense layer of proteins
anchored in microfilaments of the cytoskeleton
resists seperation during contractile activities
Adhesion belts

Question 3

Desmosomes

Answer 3

Connect between cells by embedding into intermediate filaments (keratin)
Prevent epidermal cells from separating under tension
Cardiac muscle cells from pulling apart during contraction

Question 4

Hemidesmosomes

Answer 4

Integtim embed in keratin inside the cell and to the protein laminin in the basement membrane
Don’t link adjacent cells, but anchor them to the basement membrane

Question 5

Gap Junctions

Answer 5

Contain membrane proteins called connexins
Form tiny fluid-filled tunnels called connexons and connect neighboring cells
Separated by a very narrow intercellular gap(space)
Communication of cells within the tissue
Signals travel through the connexons