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Flashcards in Mokrzan Deck (50)
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1
Q

4 families of ECM

A
  1. Collagen
  2. Elastin
  3. Glycoproteins
  4. Proteoglycans
2
Q

2 types of glycoproteins

A
  1. Fibronectin

2. Laminin

3
Q

Collagen is ___% of total body ____?

A

30%

Protein

4
Q

Structure of collagen = _______

Stabilized by ________

A

Triple-helical

Crosslinks

5
Q

Synthesis of collagen is affected by ____

A

Physiologic conditions (ex. diet or mechanical stress) [Frequently remodeled]

6
Q

A genetic mutation that causes the _____ in ___ collagen to be replaced by another AA is called _____ ____

A

Glycine
Type I
Osteogenesis/dentogenesis imperfecta

7
Q

Predominant ECM molecule in blood vessels

A

Elastin

8
Q

ECM component found in skin, lungs, intestines

A

Elastin (found in organs that require elasticity)

9
Q

Elastin is stabilized by ____

A

2-way crosslinks

10
Q

How long is elastin synthesized for

A

Stops after adolescence

11
Q

Function of fibronectin

A
Facilitates communication btwn IC and ECM
Cell adhesion
Cell growth
Migration
Wound healing
12
Q

Fibronectin binds to _____

A

Other ECM molecules & integrin molecules on cells

13
Q

Types of fibronectin

A

At least 20 known types including soluble and insoluble forms

14
Q

Fibronectin produced by

A

Alternative splicing of a single precursor mRNA

15
Q

Where is laminin primarily found?

A

Basal lamina

16
Q

Function of laminin

A

Gives structural support to ECM

17
Q

Major component of basement membranes in epithelial and muscle tissues

A

Laminin

18
Q

Laminin binds to cells via _____

A

integrin family of proteins

19
Q

Diseases of defective laminin

A

Muscular dystrophy
Defects of kidney filter
Epidermolysis bullosa - lethal skin blistering disease

20
Q

Proteoglycans are the __-___ of the ECM

A

gel-formers

21
Q

Proteoglycans have many ____ charges which attracts ____ & ____. Result is ____ of ECM that provides ____ & _____

A
Negative
Cations
Water
Hydration
Rigidity
Durability
22
Q

Proteoglycans make up ___% of ECM proteins, but because of _______, ___ ____ fill most of ECM

A

<10%
hydrophilicity
GAG chains

23
Q

Proteoglycans can combine to form _____

A

aggrecans

24
Q

Other functions of proteoglycans

A

Can bind growth factors
Regulate enzyme activity
Act as co-receptors

25
Q

Types of diseases caused by proteoglycan defects

A

Lysosomal storage diseases

26
Q

3 types of cell junctions

A
  1. Tight junctions
  2. Anchoring junctions
  3. Gap junctions
27
Q

Types of anchoring junctions

A

Adherens junctions
Desmosomes
Hemidesmosomes
Focal adhesions

28
Q

This type of tissue is particularly rich in cellular junctions

A

Epithelial tissues

29
Q

Type of cell-cell junction found in all epithelia

A

Tight junctions

30
Q

Tight junctions _______ intercellular permeability and ______ cell membrane polarity

A

Severely limit

Maintain

31
Q

Tight junctions are formed by

A

Sealing strands anchored in the membrane

32
Q

Tight junctions permeability to macromolecules and small molecules

A

Active transport required for solutes to cross epithelial barrier
Junctions are impermeable to macromolecules
Permeability to small molecules varies greatly depending on the # of sealing strands and transmembrane proteins (occludin and claudin families) that comprise them

33
Q

Anchoring junctions bind what and are found where

A

Bind cells to each other and to ECM

Found in all tissues, especially those subject to mechanical stress

34
Q

Adherens junctions are found primarily in ____

A

epithelia

35
Q

Adherens junctions form a continuous ____ ___ and are required for _____ _____ formation and ____ ____ formation in _____

A

Adhesion belt
Tight junctions
Epithelial tube
Morphogenesis

36
Q

Transmembrane proteins in adherens junctions and desmosomes

A

Cadherins

37
Q

Adherin junctions connect bundles of ____ filaments (_____)

A

Actin

Contractile

38
Q

Desmosomes are found primarily in _____

A

Epithelia and muscle cells

39
Q

Desmosomes contribute to

A

Tissue strength & durability

40
Q

Hemidesmosome function

A

Bind cells to ECM

Attach junctional epithelium to tooth enamel

41
Q

Transmembrane proteisn in hemidesmosomes

A

Integrins

42
Q

Focal adhesions functions

A
Spot-type junctions that link cell cytoskeleton to ECM
Important in Cell migration
Motility
Differentiation
Proliferation
Orthodontic tooth movement
43
Q

How many proteins can focal adhesions contain

A

As many as 100

44
Q

Response of focal adhesions to IC or EC signals

A

They can form, change, or disappear in response (Dynamic)

45
Q

External mechanical signals are transmitted via

A

Integrin receptors in focal adhesions

46
Q

Gap junctions are found primarily in _________

A

All cells except skeletal muscle and blood cells

47
Q

Gap junction permeability

A

Allow small molecules and electrical charges to pass directly from cell to cell
Varies with the identity and combination of connexins present

48
Q

Gap junction permeability regulated by

A

Intra- and extra- cellular signals

49
Q

Channels in gap junctions are called ____ and are ____ of ____ proteins

A

Connexons
Hexamers
Connexin

50
Q

Gap junctions main function

A

Allow cells of a given tissue to function together quickly and in a coordinated fashion