Biochem - Connective Tissue Flashcards Preview

MBBS - Year 1 > Biochem - Connective Tissue > Flashcards

Flashcards in Biochem - Connective Tissue Deck (66)
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1
Q

Types of connective tissue diseases

A

Sarcoma
Autoimmune
Congenital
Acquired

2
Q

Examples of autoimmune connective tissue diseases

A

RhA

SLE

3
Q

Examples of congenital connective tissue diseases

A

OI
Ehlers Danlos syndrome
Marfans

4
Q

Examples of acquired connective tissue diseases

A

Scurvy
OA
Tendinitis

5
Q

Characteristics of connective tissue

A
Highly specialised 
Mechanical support, movement 
Contains blood vessels, nerves
Arena for fighting infection 
Regulates cell behaviour
6
Q

Connective tissue components

A

Fibres
‘Ground substance’
Matricelluar proteins
Spp cells

7
Q

Connective tissue fibres

A

Collagen

Elastic fibres

8
Q

‘Ground substance’

A

Everything except collagen e.g. proteoglycans

9
Q

Spp cells found in skin, tendons and ligaments

A

Fibroblasts

10
Q

Spp cells found in cartilage

A

Chondrocytes

11
Q

Spp bones found in bone

A

Osteocytes (osteoclasts and osteoblasts)

12
Q

Structure of elastic fibres

A

Heavily cross linked

13
Q

Components of elastic fibres

A

Elastin
Fibrillins (1-3)
Fibulins
Matriculates Associated Glycoproteins (MAGP)

14
Q

Roles of elastic fibres

A

Structure

Regulation (growth factor signalling)

15
Q

Conditions caused by defects in elastin

A

Cutis laxa
Wiliams syndrome
Supravalvular aortic stenosis

16
Q

Conditions caused by defect in Fibrillin-1 (fibrillinopathies)

A

Marfan syndrome
Acromelial dysplasia
Stiff skin syndrome
Progeroid syndrome

17
Q

What is proteoglycan important for

A

Connective tissue material properties

18
Q

Features of proteoglycan

A

Variable in size
Confer viscoelastic properties
Hold water in tissue
Interact w. cells, cytokines and collagen

19
Q

Main structural component of connective tissue

A

Collagen fibrils

20
Q

Structure of collagen fibrils

A

3 alpha chains arranged in triple helix secreted into ECM

Each alpha chain is a single gene product

21
Q

Types of collagen

A
Type I
Type II
Type III
Type IV
Type V
22
Q

Type I collagen

A

Approx 90% of the collagen in the body is type I
Main component of bone, dermis, tendons and ligaments
Utilised in wound healing

23
Q

Type II collagen

A

Formed of copolymers

Main component of cartilage and is also found in the cornea and vitreous humour

24
Q

Type III collagen

A

Found in arteries and hollow organs, often in combination with type I
Also called reticular fibres

25
Q

Type IV collagen

A

Forms basement membrane

26
Q

Type V collagen

A

Found in cell surfaces, placenta and hair

Helps organise type I collagen in the dermis

27
Q

EDS is associated with a mutation in which type of collagen

A

V

28
Q

Scurvy

A

Vit C deficiency

Shows importance of collagen hydroxylation

29
Q

Presentation of scurvy

A
Bleeding gums 
Loss of teeth 
Skin lesions, bruises 
Poor wound healing 
Joint pain and weakness
30
Q

What differs in each type of connective tissue

A

Collagen composition and organisation

31
Q

Collagen composition in skin

A

60% Type I collagen

30% Type II collagen

32
Q

Organisation of collagen in skin

A

Meshwork of fibres

33
Q

Collagen composition in tendon/ligaments

A

90% Type I collagen

5% Type II collagen

34
Q

Organisation of collagen in tendon/ligaments

A

Parallel fibres

35
Q

Collagen composition in bone

A

90% Type I

2% Type II

36
Q

Organisation of collagen in bone

A

Sheets (lamella)

37
Q

Collagen composition in cartilage

A

95% Type II collagen

38
Q

Organisation of collagen in cartilage

A

Meshwork of fibres

39
Q

Structural and biomechanical changes in OA cartilage

A

Loss of proteoglycans
Collagen ‘fibrillation’
Enzymatic degradation

40
Q

Common site of tendon pathology

A

Enthesis/ insertion as it is a region of stress conc

41
Q

Common syndromes affecting enthesis

A

Tennis elbow
Golfer’s elbow
Jumpers knee
Osgood-Schlatters

42
Q

Tendinopathy

A
A degenerative condn 
Loss of collagen organisation and reduced fibril diabetes 
Changes I collagen content 
Vascular (and nerve) infiltration 
Failure to repair
43
Q

What mostly causes OI

A

Defects in Type I collagen genes

44
Q

Type I OI

A

Mildest and most common form
Quantitative defect
Half the amounts of normal type I collagen

45
Q

Type II OI

A

Most severe - death in utero
Qualitative defect - missense mutation
Abnormal Type I collagen

46
Q

EDS types

A
Classical 
Benign hyper mobility 
Vascular 
Kyphoscoliosis 
Arthrochalasia 
Dermatosperaxis
47
Q

Dx of EDS (& other genetic condns)

A
Detailed clinical and family hx 
Physical examination 
Skin biopsy and histology 
Biochemical analysis e.g. culture and urine analysis 
Molecular analysis of spp genes(s)
48
Q

Treatment of EDS and connective tissue disorders

A

Vascular damage is most important complication
Control risk factors
Drugs

49
Q

Controlling risk factors as treatment for connective tissue disorders

A

Healthy lifestyle
Protection (bandages, splints, padding)
Avoidance of contact sports and heavy exercise
Supplementation of vitamin c

50
Q

Drugs to treat connective tissue disorders

A

Beta blockers may reduce aortic dilation

51
Q

Why should NSAIDs and aspirin be avoided when treating connective tissue disorders

A

Platelet function and clotting

52
Q

What is EDS

A

A rare autosomal ctd that is primarily characterized by skin hyperextensibility, abnormal wound healing/atrophic scars and joint hypermobility. 90% of pts have all criteria listed.

53
Q

Clinical symptoms of Marfan’s

A
Scoliosis 
Chest deformities 
Arachnodactyly (long fingers)
Tall, thin 
Joint hypermobility 
Craniofacial abnormalities 
Cardiovascular defects 
Ocular defects
54
Q

Developmental problems of collagen

A

Chondrodystrophies

Collagenopathies

55
Q

Structural problems of collagen

A

OI
EDS
Marfan’s

56
Q

Condns associated with collagen maintenance and repair

A

Osteoporosis
OA
Tendinopathy

57
Q

Ligaments vs tendons

A

Tendons attach muscle to bone but ligaments attach bone to bone

58
Q

Function of tendons

A

Tendons are slightly elastic, allowing to transmit forces from muscle to bone

59
Q

Function of ligaments

A

Help stabilise a joint by restricting excess movement and minimising risk of injury

60
Q

Structure of tendons

A

Collagen fibril –> subfasicle –> fascicle —> tertiary fibre bundle

61
Q

Endotenon

A

Connective tissue separating fascicles

Facilitate gliding of bundles independently against one another during movement

62
Q

Epitenon

A

Found outside tertiary fibre bundles

63
Q

Types of entheses

A

Fibrocartiliginous

Fibrous

64
Q

Zones in fibrocartilaginous entheses

A

Fibrous connective tissue (the tendon)
Uncalcified fibrocartilage
Calcified fibrocartilage
Bone

65
Q

Sharpey’s fibres

A

Where calcified fibrocartilage interdigitates with bone

66
Q

Fibrous entheses

A

Tendons merge with the periosteum before attaching by fibrous tissue to the bone

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