Structure and Biochemistry of Connective Tissue

Question 1

What embryological tissue is connective tissue derived from?

Answer 1

Mesoderm

Question 2

What properties define connective tissues?

Answer 2

Cells positioned far apart, surrounded by extra-cellular matrix

Question 3

What is the major cell type found in most connective tissues?

Answer 3

Fibroblasts

Question 4

What extra-cellular matrix is produced by fibroblasts?

Answer 4

Fibres containing collagen and elastin

Ground substance

Question 5

What makes up ground substance?

Answer 5

Water and proteoglycans and metabolites

Question 6

Where are osteocytes found?

Answer 6

Bone

Question 7

Where are chodrocytes found?

Answer 7

Cartilage

Question 8

Where are adipocytes found?

Answer 8

Fat

Question 9

Which connective tissue cell type proliferates in response to injury?

Answer 9

Fibroblasts (immature)

Question 10

What are mesenchymal cells?

Answer 10

Undifferentiated stem cells

Question 11

What is the function of adipocytes and what are the two types, and from which cell do they develop?

Answer 11

Adipocytes synthesise and store lipids
Unilocular adipocytes = White cells
Multilocular adipocytes = Brown cells (high in neonates)
Develop from mesenchymal cells

Question 12

Name the two types of soft connective tissue?

Answer 12

Loose (low collagen)

Dense (high collagen)

Question 13

Name the subdivisions of loose connective tissue?

Answer 13

Areolar (gas exchange)
Adipose
Reticular (lymph/liver/spleen)
Synovial

Question 14

Describe synovial fluid?

Answer 14

High in blood plasma, it contains hyaluronan and glycoproteins (proteoglycan aggregates)

Question 15

Name the subdivisions of dense connective tissue?

Answer 15

Irregular - dermis of skin

Regular (high in collagen and vit C) - including tendons/ligaments/fibrous capsule

Question 16

Name and describe the three types of skeletal connective tissue?

Answer 16

Bone - haversian/woven
Cartilidge - hyaline/elastic/fibrocartilage
Dental - Dentine/enamel

Question 17

Describe osteoarthritis?

Answer 17

Acts on hyaline cartilage
Slow degeneration
Wear and tear

Question 18

Describe rheumatoid arthritis?

Answer 18

Acts on synovial membrane/hyaline cartilage
It is an autoimmune disorder
It is aggressive in progression

Question 19

Tendonitis of the lateral epicondyle is commonly referred to as?

Answer 19

Tennis elbow

Question 20

Tendonitis of the medial epicondyle is commonly referred to as?

Answer 20

Golfer’s elbow

Question 21

Where is type I collagen found?

Answer 21

Ubiquitous (everywhere) - including bone

Question 22

Where is type II collagen found?

Answer 22

Main component in cartilage formation

Vitreous humour of the eye

Question 23

Where is type VI collagen found?

Answer 23

Basal laminae

Question 24

In hyaline cartilage what do proteoglycans provide?

Answer 24

Flexibility and resilience to compression

Question 25

In hyaline cartilage what do collagen fibres provide?

Answer 25

Rigidity and tensile strength

Question 26

Where and how does hyaline cartilage obtain nutirents?

Answer 26

Comes from the synovial fluid and subcondral bone | Via accelerated diffusion

Question 27

What does accelerated diffuse dependent upon?

Answer 27

Mobilisation of the joint

Question 28

How does osteoarthritis lead to chondrocyte matrix breakdown?

Answer 28

Relieves the set constant pressure that the chonrocytes require to maintain their structure

Question 29

What substances is collagen made up of?

Answer 29

Glycine Proline/hydroxyproline Hydroxylysine

Question 30

Pro-collagen is converted via pro-collagen peptides into what?

Answer 30

Tropo-collagen

Question 31

Defects in the pro-collagen peptides can lead to which condition?

Answer 31

Ehlers-Danlos syndrome type VII

Question 32

What secondary protein structure makes up collagen?

Answer 32

Type II - trans helix (with hydrogen bonds)

Question 33

Vit C deficiency can lead to which condition?

Answer 33

Scurvy

Question 34

Collagen is structurally stabilised via lysine residue reactions and lysyl oxidase, a defect in lysyl oxidase leads to what conditions?

Answer 34

Ehlers-Danlos syndrom type V | SCAD

Question 35

What is the protein to carbohydrate ratio in proteoglycans?

Answer 35

10:90

Question 36

Name the type of proteoglycan primarily found in cartilage?

Answer 36

Aggrecan

Question 37

Name the and describe the short glycosaminoglycan (GAG) chains found on aggrecan?

Answer 37

Keratan-sulphate Galactose-GlucNac Every other sugar has a negative charge

Question 38

Name the and describe the long glycosaminoglycan (GAG) chains found on aggrecan?

Answer 38

Chondroitan-6-sulphate Glucoronic acid-GlucNac Every sugar is negatively charged

Question 39

What part of the proteoglycan interacts with hyluronan and via which type of chemical bond?

Answer 39

G1 N-terminal | Ionic bond

Question 40

How do proteoglycan aggregates present in the extracellular matrix?

Answer 40

Multimolecular aggregates with very high negative charge

Question 41

What is the function of proteoglycan aggregates?

Answer 41

Retention of water in the extracellular matrix

Question 42

Describe the term 'swelling pressure'?

Answer 42

Proteoglycans are restrained from swelling by the tight collagen meshwork, creating a pressure

Question 43

Describe the 'dampening effect'?

Answer 43

Bottle-brushes of proteoglycans sliding past each other causing a large frictional drag - the cartilage deforms slowly and gradually under the load