Brainscape's Knowledge GenomeTM

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


See full index

BMS 300 > Cell Junctions and Epithelial Tissue > Flashcards

Cell Junctions and Epithelial Tissue Flashcards

1
Q

What is the function of Gab Junctions (GJ)?

A

Mediates cell-to-cell communication through combined intercellular channels (H2O) that permit the transfer of ions and small molecules

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

What is the structure of GJ?

A

Composed of connexins which are hexamers of medium-sized families of integral proteins

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

GJ couple cells both _______ and _______

A

Electrically and mechanically

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

Where are GJs found?

A

Low resistance ion pathway joining excitable cells (nerve and muscle) and joining virtually all cells in solid tissues

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

What permits tissue-specific GJs?

A

Multiple isoforms of connexins
Ex: Informs have similar functions but in different tissues, cardiac and skeletal systems both contract

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

What do different combinations of connexins do?

A

Creates channels that differ in permeability and regulation
Ex: temperature, flow of H2O, open and closes

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

How is regulation mediated?

A

Changes in pH or Ca2+ or signals (neurotransmitters)

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

What is the difference between GJ and tight junctions (TJ)?

A

GJ is seen as an area of close plasma membrane apposition, TJ joins the cells together

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

What is the function of TJ?

A

TJ holds the cells closely together near the apex to prevent molecules from leaking across the epithelium
- Like a fence, traffic is controlled to go a certain way

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

What are the types of TJ?

A

Claudin (main transmembrane protein)
Occludin (second major transmembrane)
Zonula Occludens (large scaffold protein that provides a structural support)

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

What is the purpose of claudins?

A

A selectively permeable seal

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

How do claudins function?

A

There are over 20 claudin protein families in humans that express different combinations in different epithelia to confer particular permeability properties
Ex: Kidney-specific claudin permits Mg2+ to be reabsorbed from urine into the blood

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

Claudins are dysregulated in various ______

A

Cancer
Ex: IBD- claudin dysregulation correlates with an increased intestinal permeability, sustained activation of inflammation

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

What happens if there is impaired barrier function?

A

Luminal bacterial leakage inversely exacerbates inflammation
Epidermal growth factors influx contributes to tumorigenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens if there is a pathogenic breach?

A

Overactive inflammatory response which also changes claudin expression leading to impaired barrier function

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

___ influx contributes to tumorigenesis

A

Epidermal growth factor (EGF)

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

What recovers epithelial claudin expression and promotes mucosal healing?

A

Probiotics

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

What are anchoring junctions?

A

Complexes that adhere cells to other cells or the extracellular matrix

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

What is the structure of anchoring junctions?

A

Provides a strong membrane-spanning structure that is tethered inside the cell to the tension-bearing filaments of the cytoskeleton

20
Q

What are the types of anchoring junctions?

A

Laterally attached to the site of cell: Adherens Junction & Desmosomes
The surface of cell, connects to the matrix: Hemidesmosomes & Focal adhesion

21
Q

What is TJ plaque?

A

Internal attachment

22
Q

What is TJ transmembrane?

A

External attachment
Ex: Claudins

23
Q

What are Adheren Junctions?

A

Connected to the cytoskeleton by actin

24
Q

What are Desmosomes?

A

Connected to the cytoskeleton by intermediate filaments

25
Q

What are Hemidesmosomes?

A

Connected to the cytoskeleton by intermediate filaments

26
Q

What are Focal Adhesions?

A

Connected to the cytoskeleton by actin

27
Q

What Anchoring Junctions contain cadherins transmembrane proteins?

A

Adherens Junction and Desmosomes

28
Q

What Anchoring Junctions contain integrins transmembrane proteins?

A

Hemidesmosomes and Focal Adhesions

29
Q

Where are the AJs located?

A

AJs are located below the TJ, the formation of AJs is a prerequisite for TJ assembly

30
Q

What is the structure of cadherins?

A

The structure is dependent on Ca2+ ions

31
Q

What happens if mutation disrupts the production or function of E-cadherins?

A

Often found in cancer cells and thought to help make them malignant due to the gain of invasiveness and metastatic potential of cells

32
Q

What role do Desmosomes play?

A

Play a critical role in tissues subjected to mechanical stress like the myocardium, bladder, and skin

33
Q

What are hemidesmosomes and focal adhesion?

A

Aids in the interaction of a cell-extracellular matrix

34
Q

What are the functions of cell junctions?

A
  1. Attachment- mechanical support, can move to other cells if stressed
  2. Separation- protection & traffic regulation
  3. Communication between cells-
    mechanical, metabolic, etc
  4. Cell polarity- Orientation of the cell to establish basal surfaces
35
Q

What is Epithelial Tissue?

A

Sheets covering all the surfaces of the body exposed to the outside world and lining the outside of the organs

36
Q

Classification of cells

A

The first name: denotes the number of cell layers present
Second name: Shape of the cell

37
Q

What is the Simple Squamos?

A

The type of epithelium typically lines blood vessels and body cavities and regulates the passage of substances into underlying tissues

38
Q

What is Simple Cuboidal?

A

This type of epithelium is typically found in glandular (secreting) tissue and kidney tubules

39
Q

What is Simple Columnar?

A

This type of epithelium is often specialized for absorption and usually apical cilia or microvilli, these cells line your stomach and intestines

40
Q

What is Stratified Squamos?

A

This type of epithelium usually has protective functions, including protection against microorganisms from invading underlying tissue and/or protection against water loss
- Makes up the outer layer of skin

41
Q

What is Stratified Cuboidal?

A

This type of epithelium is not as common and is found in the excretory ducts of your salivary and sweat glands

42
Q

What is a Stratified Columnar?

A

This type of epithelium is not as common and is seen in the mucous membrane lining of your eyelids, where it’s protective and mucus-secreting

43
Q

What is a Pseudostratified Columnar?

A

This type of epithelium lines your upper respiratory tract and usually has a lot of cilia

44
Q

What is Transitional Epithelium (Urothelium)?

A

This type of epithelium is made up of several layers of cells that become flattened when stretched
- It lines most urinary tract and allows the bladder to expand

45
Q

Characteristics of Epithelial tissue

A

Specialized contacts, polarity, avascular, innervated, & regenerative

BMS 300 (8 decks)

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