Epithelia - Lateral Surface Specialisations Flashcards

1
Q

How are epithelial cell specialised to join together?

A

Epithelial cells have junctional specialisations

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2
Q

What makes up the junctional specialisations of epithelial cells?

A

Cell membrane proteins and lipids

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3
Q

What are the three types of junctional specialisations?

3

A

Tight junctions

Gap junctions

Anchoring junctions

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4
Q

What is another name for tight junctions?

A

Occluding junctions

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5
Q

Where are occluding junctions located?

A

Between two plasma membranes

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6
Q

Write a note on occluding/tight junctions.

3

A

Adhesion belt attaches to terminal web

Prevents passage of water and solutes

Isolates wastes in the lumen

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7
Q

What does a tight junction prevent the passage of?

2

A

Water

Solutes

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8
Q

What does a tight junction do with wastes?

A

They are isolated in the lumen

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9
Q

What does a tight junction isolate in the lumen?

A

Wastes

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10
Q

What is the role of gap junctions?

A

They allow for rapid communication

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11
Q

Write a note on gap junctions

A

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

Allow ions to pass so cells can communicate

Allow the coordination of cilia beating

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12
Q

What hold gap junctions together?

A

Channel proteins

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13
Q

Name two channel proteins that hold together gap junctions.

A

Junctional proteins

Connexons

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14
Q

What passes through gap junctions?

A

Ions

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15
Q

Why do gap junctions allow ions to pass through?

A

So cells can communicate

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16
Q

What are desmosomes composed of?

3

A

Cell adhesion molecules

Dense areas

Intracellular cement

17
Q

How many types of desmosomes are there?

18
Q

Name the two types of desmosomes.

A

Spot desmosomes

Hemidesmosomes

19
Q

What are the two roles of spot desmosomes?

A

Tie cells together

Allow bending and twisting

20
Q

What is the role of hemidesmosomes?

A

Attach cells to the basal lamina

21
Q

What is the role of desmosomes?

A

They attach cells together or to extracellular material

22
Q

What is the role of the basal surface?

A

It attaches epithelial cell to extracellular matrix adhesion molecules

23
Q

What is found beneath the basal surface?

A

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

24
Q

What forms the basal membrane?

A

Epithelial cells and underlying connective tissue

25
What is the role of the basal membrane?
Separates the epithelium from the underlying connective tissue
26
How may the basal membrane appear?
It may be folded
27
What are the two layers of the basal membrane called?
Basal lamina Reticular lamina
28
What are the two layers of the basal lamina called?
The lamina lucida The lamina densa
29
What is the lamina lucida also called?
Clear layer
30
What is the lamina densa also called?
Dense layer
31
Give three points on the lamina lucida/clear layer.
Thin Secreted by epithelia Barrier to CT proteins
32
Give three points on the lamina densa/dense layer
Thick fibers Produced by connective tissue Strength and filtration
33
What produces the lamina lucida/clear layer?
They are secreted by epithelia
34
What produces the lamina densa?
It is produced by connective tissue
35
Where are stem cells found?
Stem cells are found in the basal layer of stratified epithelia
36
What makes up epithelial tissue?
Epithelial cells that are attached along their sides