Connective tissue biology

Question 1

where is connective tissue located?

Answer 1

under the epithelium

Question 2

what is the outer casing of connective tissue called?

Answer 2

basal lamina

Question 3

what is the structure of connective tissue?

Answer 3

loosely packed, unspecialised cells embedded in a relatively large amount of extracellular matrix

Question 4

connective tissue is the main component in what?

Answer 4

cartilage and bone

Question 5

connective tissue is the minor component in what?

Answer 5

brain and spinal chord

Question 6

connective tissue cells are usually of what origin?

Answer 6

mesenchymal - a type of undifferentiated connective tissue

Question 7

what do fibroblasts do?

Answer 7

secrete ECM rich in collagen and other macromolecules. It migrates and proliferates readily in wounded tissue and in tissue culture.

Question 8

describe the structure of fibroblasts

Answer 8

actin round the edge
intermediate filaments and microtubules (tubulin) span the entire cell (denser round nucleus)

Question 9

what is the main intermediate filament in fibroblasts?

Answer 9

vimentin

Question 10

what does vimentin do in fibroblasts?

Answer 10

gives cell shape and moves organelles round the cell

Question 11

what are the junctions between the fibroblasts and the extracellular matrix called?

Answer 11

integrin receptors

Question 12

what happens to fibroblasts as they age?

Answer 12

produce a different ECM -> different types of collagen produced

Question 13

explain the heterogeneity of fibroblasts

Answer 13

there are subtypes that have different size, shape, proliferative activity, motility, attachment, collagen, ECM proteins, actin isoforms

Question 14

what can fibroblasts differentiate into?

Answer 14

Bone cells - osteoblast/osteocyte
Fat cells - adipocyte
Smooth muscle cells
Cartilage cells - chondrocyte

Question 15

what are the functions of the extracellular matrix?

Answer 15

support, regulation and development

Question 16

how is the extracellular matrix involved in regulation?

Answer 16

cell polarity (as has basal lamina)

cell division (tells cells to divide)

adhesion (cells stuck to basal lamina)

motility (if matrix too thick or thin cells wont be able to migrate)

Question 17

how is the extracellular matrix involved in regulation?

Answer 17

cells migrate through the matrix and are told to differentiate

Question 18

what is the main protein in oral connective tissue?

Answer 18

collagen

Question 19

oral connective tissue is mainly made up of what?

Answer 19

extracellular matrix

Question 20

what is a proteoglycan?

Answer 20

Protein with a small sugar group attached

Question 21

what are the main proteoglycans in oral connective tissue?

Answer 21

decorin
fibromodulin
lumican
CD44

Question 22

what are GAGs - glycosaminoglycans

Answer 22

Repeating disaccharide chain structure. Has an amino sugar and a uronic acid. Highly -vely charged and can be sulphated or carboxylated

Question 23

what is the main GAG in oral connective tissue?

Answer 23

hyaluronan

Question 24

what is the structure of hyaluronan (GAG)?

Answer 24

• Non-sulphated GAG
  Disaccharide repeating units of N-acetylglucosamine linked with glucuronic acid

Question 25

what is the function of hyaluronin (GAG)?

Answer 25

binds water molecules

Question 26

collagen is a fibrous protein. 90% of collagen is what types?

Answer 26

I, II and III

Question 27

what is the structure of collagen?

Answer 27

3 coiled subunits of amino acids making a triple helix

Question 28

what amino acids are in the repeating subunits of collagen?

Answer 28

glycine
proline
hydrxyproline
hydroxylysine

Question 29

what is the function of glycine in collagen subunit?

Answer 29

small so small gaps when packing making it strong

Question 30

what is the function of proline in collagen subunit?

Answer 30

fixed angle allows helix formation

Question 31

what is the function of hydroxyproline in collagen subunit?

Answer 31

fixed angle allows helix formation

Question 32

what is the function of hydroxylysin in collagen subunit?

Answer 32

stabilises side by side packing

Question 33

understand the biosynthesis of collagen

Answer 33

○ Ribosome makes series of amino acid forming pro-α chain
○ In golgi apparatus
○ Hydroxylation of selected lysines and prolines
○ Glycosylation of selected hydroxylysines
○ Assemble 3 pro-α chains
○ Procollagen triple helix formation - propeptides twist together
○ In secretory vesicle for secretion
○ Cleavage of propeptides once outside the cell
○ Collagen self-assembles into fibril
○ Aggregation of collagen fibrils to form a collagen fibre

Question 34

what is sclerodoma?

Answer 34

excessive deposits of collagen from growth factors

Question 35

what is oral submucosa fibrosis?

Answer 35

scarring of the oral cavity associated with chewing areca nut. Increase in type III then type I collagen

Question 36

what is hereditary gingival firbomatosis?

Answer 36

collagen and connective tissue overgrows the teeth

Question 37

what is osteogenesis imperfecta?

Answer 37

insufficient collagen, brittle bones

Question 38

what is ehlers-danlos syndrome?

Answer 38

defect in collagen synthesis, flexible joints, skin and tendons : Unstable teeth
insufficient collagen

Question 39

what is collagenopathy?

Answer 39

insufficient collagen, cleft palates and small lower jaws

Question 40

what is scurvy and how does it affect the body?

Answer 40

dietary deficiency in vitamin C

Vitamin C needed in hydroxylation of proline to hydroxyproline

Form too few hydrogen bonds in collagen

Teeth weakness and malformation

Blood vessels weakened -> bleeding