Epithelia - Lateral Surface Specialisations

Question 1

How are epithelial cell specialised to join together?

Answer 1

Epithelial cells have junctional specialisations

Question 2

What makes up the junctional specialisations of epithelial cells?

Answer 2

Cell membrane proteins and lipids

Question 3

What are the three types of junctional specialisations?

3

Answer 3

Tight junctions

Gap junctions

Anchoring junctions

Question 4

What is another name for tight junctions?

Answer 4

Occluding junctions

Question 5

Where are occluding junctions located?

Answer 5

Between two plasma membranes

Question 6

Write a note on occluding/tight junctions.

3

Answer 6

Adhesion belt attaches to terminal web

Prevents passage of water and solutes

Isolates wastes in the lumen

Question 7

What does a tight junction prevent the passage of?

2

Answer 7

Water

Solutes

Question 8

What does a tight junction do with wastes?

Answer 8

They are isolated in the lumen

Question 9

What does a tight junction isolate in the lumen?

Answer 9

Wastes

Question 10

What is the role of gap junctions?

Answer 10

They allow for rapid communication

Question 11

Write a note on gap junctions

Answer 11

They are held together by channel proteins (junctional proteins, connexons)

Allow ions to pass so cells can communicate

Allow the coordination of cilia beating

Question 12

What hold gap junctions together?

Answer 12

Channel proteins

Question 13

Name two channel proteins that hold together gap junctions.

Answer 13

Junctional proteins

Connexons

Question 14

What passes through gap junctions?

Answer 14

Ions

Question 15

Why do gap junctions allow ions to pass through?

Answer 15

So cells can communicate

Question 16

What are desmosomes composed of?

3

Answer 16

Cell adhesion molecules

Dense areas

Intracellular cement

Question 17

How many types of desmosomes are there?

Answer 17

Two

Question 18

Name the two types of desmosomes.

Answer 18

Spot desmosomes

Hemidesmosomes

Question 19

What are the two roles of spot desmosomes?

Answer 19

Tie cells together

Allow bending and twisting

Question 20

What is the role of hemidesmosomes?

Answer 20

Attach cells to the basal lamina

Question 21

What is the role of desmosomes?

Answer 21

They attach cells together or to extracellular material

Question 22

What is the role of the basal surface?

Answer 22

It attaches epithelial cell to extracellular matrix adhesion molecules

Question 23

What is found beneath the basal surface?

Answer 23

A network of protein and carbohydrate fibres is found beneath the basal surface

Question 24

What forms the basal membrane?

Answer 24

Epithelial cells and underlying connective tissue

Question 25

What is the role of the basal membrane?

Answer 25

Separates the epithelium from the underlying connective tissue

Question 26

How may the basal membrane appear?

Answer 26

It may be folded

Question 27

What are the two layers of the basal membrane called?

Answer 27

Basal lamina

Reticular lamina

Question 28

What are the two layers of the basal lamina called?

Answer 28

The lamina lucida

The lamina densa

Question 29

What is the lamina lucida also called?

Answer 29

Clear layer

Question 30

What is the lamina densa also called?

Answer 30

Dense layer

Question 31

Give three points on the lamina lucida/clear layer.

Answer 31

Thin
Secreted by epithelia
Barrier to CT proteins

Question 32

Give three points on the lamina densa/dense layer

Answer 32

Thick fibers
Produced by connective tissue
Strength and filtration

Question 33

What produces the lamina lucida/clear layer?

Answer 33

They are secreted by epithelia

Question 34

What produces the lamina densa?

Answer 34

It is produced by connective tissue

Question 35

Where are stem cells found?

Answer 35

Stem cells are found in the basal layer of stratified epithelia

Question 36

What makes up epithelial tissue?

Answer 36

Epithelial cells that are attached along their sides