ecm

Question 1

what is the extrcelullar matrix

Answer 1

complex network of proteins and carbohydrates filling spaces between cells
comprises both fibrillar and non-fibrillar components

fibrillar meaning fibre making

Question 2

functions of ECM

Answer 2

Provides physical support

influences the growth, adhesion and differentiation status of the cells and tissues with which it interacts

Essential for development, tissue function and organogenesis

Question 3

connective tissue companonets

Answer 3

ECM and component cells
collagen
multi adhesive glycoprotien
ptoteoglycans

Question 4

connective tissue examples

Answer 4

Tendon n skin - tough flexible

Bone: hard and dense

Cartilage: resilient and shock-absorbing

Question 5

disorders from ECM

Answer 5

1. Gene mutations affecting matrix proteins
2. Gene mutations affecting ECM catabolism
3. Fibrotic disorders due to excessive ECM deposition
4. Disorders due to excessive loss of ECM

Question 6

what is collagen

Answer 6

fibrous protein, strcutural protein

resist tensile force

Question 7

where is collagen found commanly

Answer 7

bone, tendon and skin

Question 8

alignment of collagen in skin

Answer 8

succesive layers at nearly right angles

Question 9

mature bone and cornea collagen alignment

Answer 9

same arrangemnet

Question 10

structure of collagen

Answer 10

three α chains, forming a triple helix. homo or hetrotrimers
can be different a chain

Question 11

how many genes does type 1 collagen have

Answer 11

two different genes - its composition is [α1(I)]2 [α2(I)]

Question 12

how many genes do type 2 and 3 have

Answer 12

one chain type – their compositions are, therefore, [α1(II)]3 and [α1(III)]3

Question 13

what is every 3rd amino acid and why

Answer 13

glycine- because smallest aa small r group of just h

small enough to fit in stiff structure

Question 14

x and y are commonly what

Answer 14

x is often proline, y is often hydroxyproline

Question 15

forming a collagen fibre

Answer 15

a chain
3 a chain
collagen fibril
collagen fibre

Question 16

what are newly synthesised collagen chains called and what do they have

Answer 16

pro-collagen
have n and c terminal propeptide
n and c mean non collagenous

Question 17

when are the n and c domains removed

Answer 17

domains are removed after secretion

but if it stays in the cell it is kept

Question 18

fibrillar collagen biosynthesis

Answer 18

1) synthesis of pro a chain
2) hydroxylation of some prolines and lysines
3) glycosylation of some hydroxylysines
4) self assemble of pro a chain
5) formation of procollagen triple helix
6) secreted
7) cleave propeptide
8) self assemble into fibril
9) aggregation of collagen to collagen fiber

Question 19

cross linking why

Answer 19

tensile strength and stability

Question 20

what aa are involved

Answer 20

lysine and hydroxy lysine

Question 21

what lysine and proline hydroxyaltion

Answer 21

fe2+ and vitimin c
contribute to hydrogen bond formation
modified in formation of covalent crosslinkages

Question 22

what does vitiman c result in

Answer 22

underhydroxylated collagens

Question 23

ehlers danlos syndrome EDS

Answer 23

inheritied connective tissue disorder causes stertchy sin and loose joints

Question 24

what disorder arises from EDS

Answer 24

mutation of collagen affecting collagen production structure and processing

Question 25

what are the fibrin associated collagens

Answer 25

type 9 and 12 | regulate organisation of collagen fibrils

Question 26

what is the function of type 4 collagen

Answer 26

network forming collagen present in all basement membranes more flexible helix is disorded so they're bendy

Question 27

how are the type 4 collagens assembled

Answer 27

n and c terminals not removed | n terminals interacts forming a network and self assemble to form an aggregate

Question 28

what are basement membranes

Answer 28

flexible, thin mats of extracellular matrix underlying epithelial sheets and tubes highly specialised extracellular matrices containing a distinct collection of collagens, glycoproteins and proteoglycans.

Question 29

function of basement membrane in kidney

Answer 29

forms Glomerular basement membrane

Question 30

what happens in diabetic nephropathy

Answer 30

accumulation of extracellular matrix leading to a highly thickened basement membrane --> This restricts renal filtration and can lead to renal failure.

Question 31

what is alport syndrome

Answer 31

mutations in collagen IV result in an abnormally split and laminated GBM which is associated with a progressive loss of kidney function and also hearing loss.

Question 32

where are basemant membranes typically found

Answer 32

surround muscle, peripheral nerve and fat cells and underlie most epithelia.

Question 33

function of elastic fibres

Answer 33

elasticity of tissues, such as skin, blood vessels and lung

Question 34

what makes up elastic fibres

Answer 34

protein elastin, and microfibrils and fibrilin

Question 35

mutation in fibrilin 1

Answer 35

marfans disorder, involves | skeletal, ocular, and cardiovascular systems

Question 36

what does marfan syndrome cause

Answer 36

arachnodactyly (spider-like fingers).

Question 37

segments of elsatin

Answer 37

hydrophobic and a helical regions rich in alanine and lysine

Question 38

what are lamins made of

Answer 38

proteins made up of an α chain, a β chain and a γ chain

Question 39

what is the functions of lamin

Answer 39

multi-adhesive proteins interact with a variety of cell surface receptors They can self-associate as part of the basement membrane matrix interact with other matrix components

Question 40

mutations in lamin chains examples

Answer 40

muscular dystrophy and epidermolysis bullosa

Question 41

what causes muscular dystrophy

Answer 41

absence of the α2 chain in laminin 2

Question 42

symptoms of it

Answer 42

hypotonia (abnormally decreased muscle tension), a generalised weakness and deformities of the joints.

Question 43

how fibronectins exist

Answer 43

insoluble fibrillar matrix or as a soluble plasma protein

Question 44

what are fibronectins

Answer 44

multi-adhesive proteins

Question 45

functions of fibronectins

Answer 45

interact with cell surface receptors and other matrix molecules regulating cell adhesion and migration wound healing and promote blood clotting

Question 46

what are proteoglycans

Answer 46

core proteins to which are covalently attached one or more glycosaminoglycan (GAG) chains.

Question 47

What are GAG made up of

Answer 47

repeating disaccharide units with one or 2 sugars being amino sugar when the oh group is swapped for amine group

Question 48

why are GAG carry high negative chrage

Answer 48

sulfated or carboxylated

Question 49

cartilage

Answer 49

matrix rich in collagen with large quantities of GAGs

Question 50

what is hyularonan

Answer 50

a GAG chain

Question 51

where is it found

Answer 51

soft connective tissue

Question 52

structure

Answer 52

a carbohydrate chain with no core protien

Question 53

polymerisation of hyularanon

Answer 53

high degree of polymerization large volume high viscousity

Question 54

role of hyularonan

Answer 54

protects the cartilage surface from damage

Question 55

what is aggrecan

Answer 55

major constituent of the cartilage extracellular matrix.

Question 56

how are the GAG in aggrecan

Answer 56

highly sulfated, increasing their negative charge. Also present are large numbers of negatively carboxyl group

Question 57

why it is negative

Answer 57

to attract na+ so water can be retained | under compression water is given up but gained when load is reduced

Question 58

osteoarthirits

Answer 58

erosive disease resulting in excessive extracellular matrix degradation.

Question 59

what happen in ...

Answer 59

cartilage over the end of bones are lost\ | aggrecan is cleaved

Question 60

what are fibrotic diseases

Answer 60

excessive production of fibrous connective tissue.