Brainscape's Knowledge GenomeTM

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


See full index

Regenerative Medicine > 2. Extracellular matrix > Flashcards

2. Extracellular matrix Flashcards

1
Q

What is the extracellular matrix?

A

The non-cellular components present within any tissue or organ
It provides essential physical scaffolding for the cellular components and initiates important biochemical and biomechanical cues that are essential for tissue morphogenesis

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

How is the ECM important for mechanical support?

A

Gives the cells a substrate that they may migrate on

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

What is the function of integrins?

A

Mediates cell adhesion to the ECM
It is involved in cell migration through the ECM

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

Name 4 parameters of ECM

A

Stiffness
Fibre orientation
Ligand presentation
Dimensionality

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

What are the fundamental components of the ECM?

A

Water
Polysaccharides
Proteins

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

What are the two main classes of macromolecules in the ECM?

A

Fibrous proteins
Proteoglycans

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

Describe proteoglycans

A

Proteoglycans consist of a protein core with carbohydrate chains linked to it
The carbohydrate chains are glycosaminoglycans (GAG) that are linked to the core protein with covalent bonds

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

Where are proteoglycans found?

A

Proteoglycans fill most of the extracellular interstitial space in the tissue, in a form of hydrate hydrogel

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

What are the main fibrous proteins in the ECM?

A

Collagen
Elastin
Fibronectin
Laminin

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

What is the most abundant fibrous protein in the ECM?

A

Collagen
It constitues up to 30% of the total protein mass

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

What is the function of collagen in the ECM?

A

Provide tensile support
Support chemotaxis
Regulate cell adhesion
Support migration
Direct tissue development

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

Which cells primarily synthesize collagen?

A

Fibroblasts, a type of connective tissue cell
The fibroblasts may alter the configuration of the collagen, by arranging it in sheets or cables

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

What type of collagen is more prevalent in mammals?

A

Collagen type 1

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

How is collagen different between species?

A

Collagen is very conserved between species, which makes both allogenic and xenogenic sources of collagen effective as biological scaffolds
They have low antigenic potential

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

Where is collagen type IV found?

A

In the basement membrane of all vascular structures

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

Which type of collagen is found in the basement membrane of all vascular structures?

A

Collagen type IV

17
Q

What is the function of collagen type VII?

A

It is the principal component of anchoring fibrils of keratinocytes to the underlying basement membrane in the epidermis

18
Q

What is the function of collagen type VI?

A

It functions as a connector of functional proteins and glycosaminoglycans to larger structural proteins, such as collagen type 1, helping to provide a gel-like consistency of the ECM

19
Q

What is the function of collagen type III?

A

It is found in selected submucosal ECM, where non-ridig structure is demanded for appropriate function

20
Q

Which fibrous protein is associated with elastin?

A

Collagen

21
Q

Which fibrous protein is associated with collagen?

A

Elastin

22
Q

What is elastin?

A

A major fibre of the ECM that provides recoil to tissues that undergo repeated stretch
Elastin = elastic = stretchy

23
Q

What is fibronectin?

A

It is important in organisation of the interstitial ECM and in cell attachment (by binding ECM to cell receptors)
It may be stretched greatly - several times over its resting length - due to cellular traction forces
Stretching of fibronectin exposes integrin-binding sites, which makes fibronectin an extracellular mechano-regulator
It is also important in cell migration during development.
It has many ligands for adhesion of many cell types, which makes it suitable for tissue repair scaffolds.
It is used as a coating protein on synthetic scaffold materials to promote host biocompatibility

24
Q

What may synthetic scaffold materials be coated with to promot host biocompatibility?

A

Fibronectin

25
Q

Where is laminin found?

A

In the ECM, especially within the basement membrane (basal lamina)

26
Q

What is the function of tenascin?

A

Promote fibroblast migration during wound healing

27
Q

What does the ECM consist of in tissues that are compliant (hollow tissue that distends with increasing volume)?

A

Collagen type I and III
Elastin
Fibronectin
= these form a relaxed network of fibers that are surrounded and embedded into a hydrogel of proteoglycans containing glycosaminoglycan chains

28
Q

Describe the senescent fibroblast

A

They are growth-arrested and resistant to apoptotic cues
They express high levels of fibronectin, fibroblast metalloproteinase, growth factors, plasminogen activator inhibitor and mitochondrial-related ROS
Chronic inflammation due to ROS and MMP destroys the integrity of elastin. Collagen fibers are crosslinked by glycosylation. This both gives stiffer tissues which are mechanically weaker, less elastic and more rigid.

29
Q

Describe the role of the ECM in acute wound healing

A

Wounds lead to vascular damage and formation of a fibrin clot, which stimulates monocyte infiltration to the damaged ECM. Monocytes are differentiated to macrophages by ECM-degradation products and cytokines. Macrophages secrete growth factors, matrix metalloproteinases and cytokines, that promote angiogenesis and stimulate fibroblast migration and proliferation, to rebuild the ECM. The fibroblasts synthesize ECM proteins. Increased mechanical stress may differentiate the fibroblasts.

30
Q

Explain the role of the ECM in tumours

A

ECM deposition and remodelling by fibroblasts make the tumours more stiff
The pro-inflammatory environment activates fibroblasts to differentiate to myofibroblasts, which promotes tissue desmoplasia (growth of fibrous or connective tissue)
Growth factors secreted by the myofibroblasts act on new collagen and elastin fibers, so they are reoriented and crosslinked, which generates more rigid fibrils

31
Q

What may degrade ECM components?

A

Matrix metalloproteinase (MMP)

32
Q

Name three types of cell-contacts that are based on integrins

A

Hemidesmosome
Focal contacts
Fibrillar contacts

33
Q

What are hemidesmosomes?

A

Intracellular protein plaques in epithelial tissue that connects the basement membrane to cytoskeletal intermediate filaments through integrins

34
Q

What are focal contacts and fibrillar contacts?

A

Specialised adhesion complexes
Involved in mechanical linkage of ECM to the actin cytoskeleon

35
Q

What are tight junctions?

A

They seal together neighboring cells in an epithelial sheet to prevent leakage of molecules between them. They form an impenetrable barrier by effectively fusing adjacent cell membranes together, so that no molecules can pass. The seal gives the tissue its barrier function (=think of the BBB, where tight junctions between BECs makes it impenetrable to large molecules)

36
Q

What are adherence junctions?

A

Adherence bundles join an actin bundle in one cell to a similar bundle in a neighboring cell. A sort of back-up for tigh junctions, that allow a connection to the actin cytoskeletin that can be used to regulate the permeability of the tissue and provide mechanical strength

37
Q

Whar are desmosome junctions?

A

Spot weld that anchors the tough intermediate filaments in one cell to those in a neighbour. Provides mechanical strength by anchoring cell-cell junctions to intermedaite filaments that are connected to the basement membrane through hemidesmosomes

Regenerative Medicine (15 decks)

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