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Flashcards in Collagen Deck (39)
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1

What is the most abundant protein in the body?

Collagen

2

What is the structure of collagen?

Three alpha chains
wind around each other to give a triple helix
come together to form microfibrils
come together to form fibrils
come together to form fibres

3

Which types of collagen are the "fibrillar" ones?

Types 1-3

4

What is the role of the fibrillar collagens?

Give strength to tissues

5

Which types of collagen are the "amorphous" ones?

Types 4-6

6

What is the most common type of collagen in the body?

Type 1

7

Where is type 1 collagen found in the body?

Hard tissues - bone
Soft tissues - tendons, ligaments, skin, blood vessels, hollow organs, sclera

8

Where is type 4 collagen found?

Basement membrane

9

What secretes type 4 collagen in the basement membrane?

Epithelial cells

10

How long does collagen synthesis take?

1-2 hours

11

What enzyme is responsible for collagen remodelling?

Collagenase

12

Give an example of an acquired disease due to defective collagen synthesis

Scurvy

13

Give examples of three inherited diseases due to defective collagen synthesis

Ehler's Danlos syndrome
Osteogenesis imperfecta
Alport syndrome

14

What is the cause of scurvy?

Vitamin C deficiency

15

How does vitamin C deficiency affect collagen synthesis?

Reduced hydroxylation of procollagen alpha chains

16

How does vitamin C deficiency affect the strength of collagen?

Reduced cross-linking between chains, microfibrils, fibrils
weaker collagen

17

Collagen in ......................... is particularly affected

Blood vessels

18

What are the symptoms of scurvy?

Porlonged bleeding
Tooth loss
Old scars becoming fresh wounds

19

Why does prolonged bleeding occur with scurvy?

Unale to heal wounds

20

Why does tooth loss occur with scurvy?

Collagen in perodontal ligament has short half-life
replaced by defective collagen

21

Why do old scars open up as fresh wounds with scurvy?

High collagen turnover in scars for 2 years after their formation
replaced by defective collagen

22

What is the cause of Ehler's Danlos syndrome?

Defective conversion of procollagen to tropocollagen

23

How are collagen fibres different in Ehler's Danlos syndrome?

Lack tensile strength, are weak

24

What are the features of skin in Ehler's Danlos syndrome?

Hyperextensible, recoils
Thin
Fragile
Susceptible to injury

25

Why is the skin hyperextensible?

Elastin fibres stretch a lot, not held in check by tethering effect of collagen
then recoil

26

What are the features of joints in Ehler's Danlos syndrome?

Hypermobile
Predisposed to dislocation

27

What are the complications of Ehler's Danlos syndrome?

Rupture of colon
large arteries
cornea

Retinal detachment

28

What is the cause of osteogenesis imperfecta?

Lack fo type 1 collagen

29

What are the features of osteogenesis imperfecta?

Fragile bones
Deformation of bones - progressive, severe
Blue sclera
Dental abnormalities
Hearing impairment

30

Why are bones fragile and deformed in osteogenesis imperfecta?

Lack of bone tissue
cannot withstand mechanical stress
break easily, deformed easily