Epithelium II

Question 1

Where on the cell are junctional complexes located?

Answer 1

Lateral and basal domains

Question 2

Where is the zonulae occludentes usually located?

Answer 2

In a band near the apical aspect (but still on lateral aspect) of cells

Question 3

What is the other name for zonulae occludentes?

Answer 3

Tight junction

Question 4

Where is the zonulae adherentes located?

Answer 4

Just below the zonulae occludentes on the lateral wall

Question 5

What is different about the distribution of the zonulae occludentes and the zonulae adhereentes compared to the other type of cellular junctions?

Answer 5

Go all the way around the cell

Question 6

What are the three key features of all junctional complexes?

Answer 6

1. Cytoskeletal element
2. Intracellular anchor proteins
3. CAMs

Question 7

What are the intracellular anchoring proteins that are found in the zonula occludens?

Answer 7

ZO (1,2,3)

Question 8

What are the cytoskeleton elements that are found in the zonula occludens?

Answer 8

Actin

Question 9

What are the cell adhesion molecules that are found in the zonula occludens?

Answer 9

Claudin and occludin

Question 10

How does H. Pylori relate to junctions?

Answer 10

Disrupts tight junctions in the stomach, irritating it

Question 11

Loss of claudin 5 is the cause of what disease?

Answer 11

Brain CAs

Question 12

Loss of claudin 9 is the cause of what disease?

Answer 12

Hearing loss

Question 13

Loss of the gene that encodes a specific claudin in renal epithelium results in what?

Answer 13

Loss of Mg—>muscle problems

Question 14

How can cholera disrupt junctional complexes?

Answer 14

damage ZO proteins in the intestines, leading to fluid loss

Question 15

What determine the amount of flow between epithelial cells?

Answer 15

amount of tight junctions (zona occludens)

Question 16

How do tight junctional complexes help to establish polarity in the cell?

Answer 16

Do not allow certain proteins (such as GLUT4 vs Na/K pumps) to cross them.

Question 17

What are the:

1. cytoskeletal elements
2. Intracellular anchoring protein
3. cell adhesion molecule

for the zonula adherens?

Answer 17

1. Cytoskeletal = actin
2. IC anchor = catenin
3. cadherin

Question 18

What are the:

1. cytoskeletal elements
2. Intracellular anchoring protein
3. cell adhesion molecule

for the Macula adherens (desmosomes)?

Answer 18

1. cytokeratin
2. intracellular attachment plaque
3. desmocollin and desmoglein

Question 19

What color do the macula adherens stain with E&M?

Answer 19

Red

Question 20

What is pemphigus?

Answer 20

Disorder where autoantibodies attack desmogleins (element of macula adherens), leading to skin blistering

Question 21

What are the:

1. cytoskeletal elements
2. Intracellular anchoring protein
3. cell adhesion molecule

for focal adhesions?

Answer 21

1. Actin
2. vinculin, paxillin, talin
3. integrin

Question 22

What are the:

1. cytoskeletal elements
2. Intracellular anchoring protein
3. cell adhesion molecule

for hemidesmosomes?

Answer 22

1. intermediate filament
2. plectin
3. integrin

Question 23

What is the function of focal adhesions?

Answer 23

Anchors cell to ECM

Question 24

What is the function of hemidesmosomes?

Answer 24

Anchors basal plasma membrane of the cell to the underlying basal lamina

Question 25

What collagen connets hemidesmosomes to the basal lamina?

Answer 25

Collagen 17

Question 26

What is bullous pemphigoid?

Answer 26

When auto antibodies attach collagen 17, leading to the destruction of the connection between the basal lamina and hemidesmosomes in the epidermis

Question 27

Based on the general blueprint for junctional complexes, what component does integrin represent?

Answer 27

CAM

Question 28

What is another name for nexuses?

Answer 28

Gap junction

Question 29

What is the function of gap junctions (nexuses)?

Answer 29

allows communication between adjacent cells (such as cardiac cells and electrical conductance)

Question 30

What are the proteins that make up gap junctions?

Answer 30

6 connexins made a connexon

Question 31

Disruptions in connexons lead to what 5 diseases?

Answer 31

1. Female infertility 2. neuropathy 3. deafness 4. congenital cataracts 5. cardiac arrhythmias

Question 32

Stipling of bacterial cells on epithelial cells from the vagina are called what?

Answer 32

Clue cells. Indicates Bacterial vaginosis

Question 33

What are the three pathways that a cell can undergo if it has DNA damage?

Answer 33

1. Repair fully/undergo apoptosis if not 2. Inhibit mitosis 3. Become malignant

Question 34

What are the four different types of mutations that lead to a loosening of the connections between epithelial cells that can lead to metastatic CA?

Answer 34

1. Cadherins are mutated and loosen 2. Cadherins are not produced 3. Loss of catenin 4. Alteration in the integrins

Question 35

How do metastases recognize where to extravasate?

Answer 35

Adhesion molecules are specific to the type of cell they will invade