Connective Tissue

Question 1

Reticular Fibers

Answer 1

Composed of type III collagen
Branched thin fibers
Highly glycosylated

Question 2

Where is type I collagen found?

Answer 2

Skin, Bone, Tendons

Question 3

Where is type II collagen found?

Answer 3

Carilage

Question 4

Where is type III collagen found?

Answer 4

Reticular fibers, various organs and blood vessels

Question 5

Where is type IV collagen found?

Answer 5

Basement membrane

Question 6

Structure of alpha collagen chains

Answer 6

Gly-X-Y
X often proline
Y often hydroxyproline

Question 7

Compared to normal collagen, lack of hydroxyproline has what effect?

Answer 7

Lowers melting point

Question 8

Vitamin C (ascorbate) is necessary for collagen because ______

Answer 8

Ascorbate is important cofactor of prolyl hydroxylase

Question 9

Where and by what are the procollagen chains of collagen cleaved?

Answer 9

Occurs in the extracellular space by procollagen peptidase

Question 10

Collagen fibers are put together into fibril by?

Answer 10

Lysyl Oxidase: cross links lysine with hydroxylysine

Question 11

T or F collagen fibrils contian multiple collagen types?

Answer 11

True: important for interactions with ECM components

Question 12

Elastic Fibers

Answer 12

Formed by polymerization of elastin molecules
Contains fibrilin
Elastin molecules linked together by lysyl oxidase

Question 13

Difference between elastic and collagenous fibers

Answer 13

Elastic fibers lack a lot of hydroxyproline

Elastic fibers give flexability while collagen fibers give structural support

Question 14

Glycosaminoglycans (GAG)

Answer 14

Repeating disaccharide structure

Found in: synovial fluid, vitreous humor and cartilage

Question 15

Proteoglycans

Answer 15

Very large, negatively charged molecules
Bind to growth factors
Form hydrated, space filling gels that resist compression.

Question 16

Proteoglycans are bound to ______ via _____

Answer 16

hyaluronan via link protein

Question 17

Proteoglycan Aggregate is composed of

Answer 17

proteoglycan monomers linked to hyaluronan

Question 18

Glycoproteins

Answer 18

form linkage between cells and ECM
RGD sequence mediates cell binding
i.e. fibronectin, tenascin, laminin

Question 19

Binding of integrins and glycoproteins

Answer 19

Glycoproteins bind to collagen network.
Integrins bind to glycoproteins (i.e. fibronectin)
Integrins (as dimers) bind to intracellular adaptors which bind to actin fillaments.

Question 20

Matrix Metaloproteases

Answer 20

require Zn++
Produced by fibroblasts, macrophages, neutrophils
Function as extracellular matrix / bone remodelling
Regulation of cell migration
Modulation of growth factors / cytokines

Question 21

Inhibitor of MMPs

Answer 21

TIMP 1- 4