Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histology > The Epithelial Tissue > Flashcards

The Epithelial Tissue Flashcards

1
Q

Where do we find epithelial cells?

A

Linings (covering outer and inner surfaces)

Glands (Complexes of epithelial cells that has a secretory function)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is special about epithelia?

A

It does not contain blood vessels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the main functions of epithelial cells?

A
  1. Protection (ex: epidermis)
  2. Absorption (ex: intestinal epithelium)
  3. Secretion (ex: glands)
  4. Control of transepithelial transport (ex: epithelium lining blood vessels)
  5. Sensation (taste buds, sensory cells of the inner ear)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the three shapes of epithelial cells?

A
  1. Squamous
  2. Cubodial
  3. Columnar
    Epithelia is also either simple or stratified (many layers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the main function of simple squamous epithelium?

A

Transport control and absorbtion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where do you find simple squamous epithelium?

A

Vessels (endothelium),
peritoneum and pleura (mesothelium),
pulmonary alveoli,
bowmans capsule of renal corpsule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the main functions of simple cuboidal epithelium?

A

Resorption and secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where do you find simple cubodial epithelium?

A

Renal tubules,
glands and their ducts,
lens epithelium,
ovary-covering epithelium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the main functions of simple columnar epithelium?

A

Resorption, secretion, protection and transport control.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where do you find simple columnar epithelium?

A

Alimentary tract
bile ducts
female genital tract
larger excretory ducts of glands.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is pseudostratified epithelium?

A

Pseudostratified epithelium is a variant of simple columnar epithelium. The cells in pseudostratified epithelium does often have different height and their nucleus at different levels. The bases of the cells are always located at the same level.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the main functions of pseudostratified epithelium?

A

Protection, secretion, sensation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where can we find pseudostratified epithelium?

A

In the repiratory tract and ductus epididymis and the taste buds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the different variants of stratified squamous epithelium?

A

Non-keratinized and keratinized.

  • In non keratinized stratified squamous epithelium all cells are living.
  • In keratinized stratified squamous epithelium the cells of the uppermost layer die (becomes hard plates).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the main function of stratified squamous epithelium?

A

Protection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where do we find stratified squamous epithelium?

A

Keratinized we find in the epidermis.

Nonkeratinized we find in the oral cavity, throat, esophagus, anus, vagina, and cornea.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is transitional epithelium (urothelium)?

A

Transition epithelium is stratified. The cells can be binucleated.

Transition epithelium can either be relaxed (bladder is relaced or empty and the cells appear stratified cubodial)

Or it can be distended (Bladder is filled and the surface flattens out and appears more stratified squamous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the functions of transitional epithelium?

A

Protection. It is very flexible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where do we find transitional epithelium?

A

We find transitional epithelium in the urinary tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How are the cells replaced in simple epithelium?

A

The cells die by apoptosis and are replaced by new cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How are cells replaced in stratified epithelium?

A

Cells of stratified epithelium migrate from the basal surface to the superficial layer where they detach from the surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are carcinomas?

A

Carcinomas are a term for cancer that has arisen from epithelial cells. Cancer does often arise from epithelial cells, due to high proliferation/renewal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are stem cells?

A

Stem cells are cells that can divide into different types of cells. They can also divide into the same type of stem cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is asymmetric division?

A

Asymmetric division produces two different daughter cells with different characteristics.

(Stem cells undergo asymmetric division as they produces one stem cell and one differentiated cell.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the difference between totipotent, pluripotent, multipotent and monopotent stem cells?

A

The number of different cells they can differentiate into.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the two main types of stem cells?

A

Embryonic and adult (somatic) stem cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What ‘‘Stemness level’’ are the embryonic stem cells?

A

Pluripotent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What stemness level are the adult somatic stem cells?

A

Multipotent, sometimes pluripotent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How can differentiated cells be transformed into stem cells?

A

Genetic reprogramming (insertion of defined genes into their DNA)

30
Q

What are two examples of diseases where stem cell therapy is used today?

A

Leukemias

Lymphomas

31
Q

What is basal lamina?

A

A layer of extracellular matrix excreted by the epithelial cells in which the epithelial cells sit. Includes transport proteins and infoldings.

32
Q

What is found on the apical surface of the epithelial cells?

A

Microvilli, cilia and transport proteins.

33
Q

Where are the stem cells found in epithelia?

A

Simple: Some on the basal lamina.
Stratified: Some cells on the basal layer

34
Q

What are microvilli and what are its functions?

A

A kind of brush border. Increases the membrane surface area for resorption.
(Found in resorptive epithelia)

35
Q

What are stereocilia?

A

Long and thick microvilli. Rare. Sensory cells of inner ear.

36
Q

What is Cilium proper?

A

Cilium proper is the part of cilia that contains axoneme (array of microtubules)

37
Q

What is basal body?

A

Basal body is a protein structure found at the base of cilia.

38
Q

What is the rootlet of cilia?

A

Bundle of protein filaments at the cilia.

39
Q

How is the axoneme of cilia built up?

A

9 peripheral microtubule doublets and 2 central microtubules.

40
Q

How is the bending of cilia initiated?

A

Movement of dynein arms coordinates sliding of microtubule doublets along each other.

41
Q

Examples of where cilia help to move something in the body.

A

Mucus with attached dust particles (respiratory tract)
Oocytes (in oviduct)
Spermatozoa (in the male reproductive tract)

42
Q

What is the function of occluding junctions or tight junctions (zonula ocludens)?

A

Sealing the space between epithelial cells; preventing the passage of molecules and water between the cell membranes.

43
Q

What is the function of anchoring junctions?

A

Stabilizing cell structure. Rigidity. Support. Do also connect to the cytoskeleton of the adjacent cells.

44
Q

What is the function of communicating (gap) junctions?

A

They make a direct opening between two neighboring cells, making it easy for the two cells to exchange molecules etc.

45
Q

What is the transmembrane linker protein in anchoring proteins called?

A

Cadherins

46
Q

What is desmoglein?

A

A family of cadherins.

47
Q

What happens in the disease pemphigus?

A

The immune system produces antibodies against desmosomal proteins, causing the cell junctions in epithelial tissue to break apart.

48
Q

What are connexons?

A

Proteins that form the pore for gap junction between two cells. The conexsones can close under conditions endangering the cell.

49
Q

What are basal cell membrane infoldings?

A

Infoldings in the basal cell membrane that increases the surface area –> more effective transport

50
Q

What proteins does the basal lamina contain?

A

Laminin
Collagen 4
Entactin

(Aslo contain the proteoglycan perlecan)

51
Q

What is the function of basal lamina?

A

Support for epithelium.
Filtering
Control of epithelial cell migration.

52
Q

What is the basement membrane?

A

Basal lamina + reticular lamina.

53
Q

What are glands?

A

Multicellular epithelial structures specialized in secretion

54
Q

What is the difference in target of secretion between exocrine and endocrine glands?

A

Exocrine: Secrete throing ducts to a defined site.
Endocrine: Secrete directly to extracellular space and to blood. No ducts.

55
Q

Where do we find desmosomes?

A

Desmosomes often occur in places that experience a lot of stress. For example the skin and intestines.

56
Q

Where are gap junctions often found?

A

In cells that spread action potential. For example in cardiac muscle and neurons.

57
Q

What do special structure do we find inside the microvilli?

A

Actin filaments that are elongated down the microvilli all the way to the apex of the epithelial cells, where they are connected to other actin filaments going the other way.

58
Q

How are the actin filaments in microvilli connected to the membrane at the top of the microvilli?

A

By the protein Villin.

59
Q

What connects the actin filaments to the membrane wall of the microvilli?

A

Myosin 1.

60
Q

What is the role of myosin 2 in the microvilli?

A

The myosin 2 can contract. And by contracting they can spread the microvilli longer from each other, increasing the surface area.

61
Q

What are the role of fibrin in microvilli?

A

Connecting the actin filaments.

62
Q

What are the stereocilia specialized in?

A

Absorption of fluids.

63
Q

How are the cilia able to beet in the same speed and tact?

A

Because the basal bodies of the cilia are connected.

64
Q

What are the two different types of anchoring junctions?

A

Desmosomes and zonula adherence

65
Q

What is the difference between desmosomes and zonula adherence?

A

Zonula adherence forms a belt-like structure around the cell (occluding junctions do the same). The zonula adherence is attached to the actin filaments of the cytoskeleton.

Desmosomes attach to the intermediate filaments of the cytoskeleton.

66
Q

Why is it often a lot of mitochondria lined along the basal surface of epithelial cells?

A

Because across the epithelial surface it is a lot of transport of fluids and other substances. The mitochondria are there to provide the energy for active transport.

67
Q

What are the difference of the reticular lamina and the basal lamina?

A

They together make up the basement membrane. But only the epithelial cells secretes the components of the basal lamina. And the connective tissue cells secrete components of the reticular lamina.

68
Q

What are the important functions of the basements membrane?

A 
Cell signaling
Tissue separation.
Attachment to underlying tissue.
Filtration.
Repair.
69
Q

What are the most important components for tight junctions?

A

Claudins/occludins and ZO proteins

70
Q

How is the cell membrane of the transitional epithelium?

A

The cell membrane of transitional epithelium is apical with stiff protein plaques called uroplakin linked to actin filaments

71
Q

Where do we find stratified cuboidal epithelium?

A

Stratified cuboidal epithelium is found primarily in the excretory ducts of sweat glands.

72
Q

What is the function of stratified cuboidal epithelium?

A

Transport and contol.

Histology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions