Lecture 5 Flashcards
(48 cards)
1
Q
Extracellular matrix
A
- Enviroment surrounding cells
- Varies between tissues
2
Q
Glycocalyx
A
- External projections of plasma membrane
- More prominent in certain cells
- More in epithelial cells
3
Q
Functions of Glycocalyx
A
- Mediator of cell - cell substratum interactions
- Mechanical protection
- Barrier to molecular movement towards the plasma membrane
- Regulatory factor binding site
4
Q
Basement Membrane (Basl Lamina)
A
- Thin, dense layer of ECM
5
Q
Location of Basement membrane
A
- Surrounds nerves, muscles, fat cells
- Underlies epithelail and endothelial tissues
- Epidermis of skin
- Lining of GI / resp tracts
- Blood vessel endothelium
6
Q
What of basement membrane made of
A
Collagen
7
Q
Function of basement membrane
A
- Structural support
- Prevention of tumor invasion
- Regulation of cell behaviour
- Angiogenesis
8
Q
ECM proteins are made of
A
Fibrous proteins
9
Q
3 major molecules in the ECM
A
- Adhesive Proteins
- Structural Proteins
- Proteoglycans
10
Q
What are the adhesive proteins
A
- Integrins
- Cadherins
11
Q
Function of adhesive proteins
A
- Hold cells together: Forms organized tissue
12
Q
What are the structural proteins
A
- Collagen
- Elastin
- Keratin
13
Q
Function of structural proteins
A
- Tensile and compressive strength
14
Q
Collagen
A
- Firmness and strength
- Glycoprotein
- Only found in ECM
- Most abundant protein in the human body
- Produced by Fibroblasts
15
Q
Elastin
A
Stretch ans retain shape
16
Q
Keratin
A
Hair and nails
17
Q
Collagen is a large family of _________
A
Fibrous glycoproteins
18
Q
What is the most abundant protein in the human body
A
Collagen
19
Q
Collagen is primarily produced by
A
Fibroblasts
20
Q
Type 1 collagen
A
Bone, skin, tendom (90%)
21
Q
Type 2 Collagen
A
Cartilage
22
Q
Type 3 collagen
A
Reticulin, blood vessels
23
Q
Type 4 collagen
A
Basement membrane
24
Q
Structure of collagen
A
- Triple helix of alpha chains
- Type 1 is in a linear fashion
- Large amount of proline residues
- Staggered alignment of rows
25
Collagen has large amount of ______ residues
proline
26
Post translational modification of collagen and the effects it has
- Hydroxylation of proline, lysine
- Increases stability of fiber
27
Collagen in the basement membrane
- Type 4
- Non helical segments
- More branching
- Terminal Globular domains
- Creates Lattice structure
- More flexible
- Binding site for interaction
28
Framework of collagen
- Found in tendons and cornea
- Insoluble framework determines mechanical properties of matrix
29
Corneal stroma
- Layers of collagen fibrils of uniform diameter and spacing arranged at right angles
30
Collagen in the cornea
- Ordered packing
- Tissue transperancy
31
Vitamin C defienccy causes
Problems with ECM structure
32
Effects of scurvy
- Bleeding gums
- Loose teeth
- Easy Bruising
- Wound healing
33
Why does Vitamin C have all these issues
Vitamin C is a cofactor for hydroxylation of collagen lysine and proline residues
34
Dermatoheliosis
- UV radiation exposure
35
Pathophysiology of Dermatoheliosuis
- Decreased Collagen synthesis
- Increased collagen degradation
- Disorganized elastin
36
What is proteoglycans made of
- Protein core + sugar chains
- Glycoaminoglycan (Amino Sugar)
37
Function of Proteoglycans
- Space filler
- Hydration
Cushioning
- Attract water
38
eg of proteoglycans
- Fibronectin
- Laminin
39
Composition of proteoglycans
More sugar than protein
40
Structure of Proteoglycans
- Sugar >>>> Protein
- Repeating disaacharide structure
- Acidic compunds
- Negative charges attract water
41
Where are proteogycans found
- Basement membranes
- Cartilage
42
Fibronectin is made up of
- 2 polypeptide chains connected by disulfisde bonds
- Modular construction
- 30 fn domains
- Has binding sites for collagen, proteoglycans
- creates interconnected network
43
Role of fibronectin In development
- Cell migration
- neural crese cells
- Organ formation
- Development of embryo
44
Laminin
- Held by disulfide bonds
- Strenghtn basement membrane
45
Spatial Dynamic properties of ECM
ECM fibrils can stretch several times their normal length
46
Temporal dynamic properties of ECM
ECM components are under continual degradation and reconstruction to allow ECM remodeling
47
MMPs
Degrade ECM components
48
