Epithelial Tissue Flashcards

1
Q

What are the features of the apical surface of an epithelial cell?

A

Exposed

Specialised with: microvilli, cilia

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2
Q

What are the features of the basal surface of an epithelial cell?

A

Attaches to the basement membrane via:

Integrins

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3
Q

What is the basement membrane?

A

Thin layer of basal lamina (and reticular fibres) secreted by epithelial cells between them and connective tissue

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4
Q

How do epithelial cells attach to the basement membrane?

A

Hemidesmosomes and focal adhesions use integrins as transmembrane proteins between the cell and the basement membrane

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5
Q

What are integrins?

A

Transmembrane proteins that attach cells to the basement membrane and through to the Extracellular Matrix.
Also, facilitate cell migration (immune patrolling) and cell signalling.

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6
Q

How do hemidesmosomes attach to the basement membrane

A

Hemidesmosomes produce transmembrane proteins (integrins) that interlock and connect cells with the basement membrane

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7
Q

How do focal adhesions attach to the basement membrane?

A

Focal adhesions anchor Intracellular actin filaments (microfilaments) to transmembrane proteins (integrins) which connect the cell to the basement membrane

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8
Q

What are the features of the lateral surface of an epithelial cell?

A

Attaches to adjacent cells via:
Tight junctions
Desmosomes
Gap junctions

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9
Q

How do tight junctions attach to adjacent cells?

What purpose does this serve?

A

Protein complexes fuse the membranes together forming a seal.
Molecules have to pass through cells

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10
Q

How do desmosomes attach to adjacent cells?

What purpose does this serve?

A

Produces transmembrane proteins (cadherins) that interlock and connect cells (also contain intermediate filaments intracellularly)
Helps strengthen the connections at other junctions and prevent stretching/twisting of cells under stress

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11
Q

How do gap junctions attach to adjacent cells?

What purpose does this serve?

A

Connexons (lined up transmembrane proteins) form channels between cells
Allows the movement of molecules for cell-to-cell communication

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12
Q

What are the 4 types of simple (single-level) epithelial cells?

A

Squamous
Cuboidal
Columnar
Psuedostratified

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13
Q

What are the 4 types of stratified (multi-level) epithelial cells?

A

Squamous
Cuboidal
Columnar
Transitional

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14
Q

Where is simple squamous epithelium found and what is it’s specific function?

A

Acts as a barrier: endothelium of vascular vessels, Bowman capsule
Secretes lubricating fluid: mesothelium
Active transport/gas exchange: type I pnuemocytes

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15
Q

Where is simple cuboidal epithelium found and what is it’s specific function?

A

Diffusion and secretion for hormones: thyroid (thyroxine), type II pnuemocytes (surfactant)
Line ducts/follicles for exocrine glands

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16
Q

Where is simple columnar epithelium found and what is it’s specific function?

A

Contain microvilli for absorption (simple columnar —> villi): alimentary/GI tract

17
Q

Where is psuedostratified epithelium found and what is it’s specific function?

A

Traps particle; secretes mucous (goblet cells), wafts cilia (ciliated epithelial cells): respiratory tract

18
Q

Where is non-keratinised stratified squamous epithelium found and what is it’s specific function?

A

Reduces water loss (remains hydrated) and protects against abrasion: openings of the skin (mouth, nostrils, anus)

19
Q

Where is keratinised stratified squamous epithelium found and what is it’s specific function?

A

Greatly reduces water loss and toxic ingress
Protects against abrasion and microbial colonisation
Found on the outer layers of skin (stratum corneum) - cornified layer of keratin

20
Q

Where is stratified transitional epithelium found and what is it’s specific function?

A

Stretches and distends: relaxed (columnar) contracted (squamous)
Protects from toxic chemicals
Found in the urinary tract

21
Q

What surfaces is epithelium tissue found?

A

Exterior (skin)
Interior open to the exterior (mucous membranes)
Interior closed to the exterior (serous membranes)

22
Q

Where are mucous membranes found?

A

Mucosa of:

Digestive tract
Respiratory tract
Urinary tract

23
Q

Where are serous membranes found?

A

Viscera of:

Peritoneum
Pleural sacs
Peritoneum

24
Q

Describe features of mucous membranes

A

Single-layered
Inner epithelium lines lumen
Surrounded by lamina propria (connective tissue) and muscularis mucosae

25
Q

Describe features of a serous membrane?

A

Double-layered (mesothelium)
Inner epithelium secretes lubricating fluid (for viscera)
Surrounded by lamina propria (connective tissue)