Connective Tissue

Question 1

What are the functions of connective tissue (CT)?

Answer 1

1. maintains cells/tissues/organs in their correct spatial arrangement when forces are applied
2. provides support, binding protection + insulation

Question 2

What are the 2 types of CT?

Answer 2

1. loose

2. dense/fibrous

Question 3

What are the 4 types of loose CT?

Answer 3

1. areolar CT
2. adipose tissue
3. reticular tissue
4. mucous tissue

Question 4

What is the arrangement + function of areolar CT (LCT)?

Answer 4

ARRANGEMENT:
fibres loosely connected in a meshwork

FUNCTION:

1. binds tissue parts
2. maintains movement + flexibility
3. structural support for organs/glands/vessels/nerves

Question 5

What is the function of adipose tissue (LCT)?

Answer 5

1. provides nutrients
2. acts as an energy store
3. protection
4. insulation

Question 6

Where can reticular tissue (LCT) be found?

Answer 6

bone marrow, spleen

Question 7

Where can mucous tissue (LCT) be found?

Answer 7

dental pulp, umbilical cord

Question 8

What are the 3 types of dense/fibrous CT?

Answer 8

1. cartilage
2. mineralised
3. blood

Question 9

Properties of dense CT:

1. In tendons + ligaments
   (a) + closely packed (b) tissue.
   (c) fibre bundles running in the (d) direction.
   Has (e) cells than loose CT
2. In the dermis (skin)
   (f) collagen fibre bundles

(a) regular/irregular?
(b)
(c)
(d) same/opposite?
(e) more/less?
(f ) regular/irregular?

Answer 9

(a) regular
(b) fibrous
(c) collagen
(d) same
(e) less
(f ) irregular

1. In tendons + ligaments
   regular + closely packed fibrous tissue.
   Collagen fibre bundles running in the same direction.
   Has less cells than loose CT
2. In the dermis (skin)
   Irregular collagen fibre bundles

Question 10

Is cartilage (DCT) innervated?

Answer 10

No

Question 11

Is cartilage (DCT) vascular or avascular?

Answer 11

Avascular

Question 12

What is the function of cartilage (DCT)?

Answer 12

provides support

has some pliability/flexibility

Question 13

What is the function of mineralised CT (DCT)?

Answer 13

provides support + protection

Question 14

Where can calcified cartilage (DCT) be found?

Answer 14

cartilage
bone
dentine
cementum

Question 15

What makes up CT?

Answer 15

cells + ECM

Question 16

What are chondrocytes?

Answer 16

cartilage cells

Question 17

What are osteoblasts?

Answer 17

bone forming cells

Question 18

What are osteocytes?

Answer 18

osteoblasts calcified in bone matrix

Question 19

What are odontoblasts?

Answer 19

dentine forming cells

Question 20

What are cementoblasts?

Answer 20

cementum froming cells

Question 21

Which other cells are found in CT?

Answer 21

macrophages
mast cells
melanocytes
adipose cells
mesenchymal cells
plasma cells
leukocytes

Question 22

What forms the ECM?

Answer 22

1. protein fibres
   eg, collagen, elastin
2. ground substance

Question 23

How are the protein fibres formed?

Answer 23

1. protein molecules synthesised by fibroblasts
2. fibroblasts secrete protein molecules into ground substance
3. the molecule aggregate into fibres
4. collagen fibres = mechanical strength
   elastin fibres = mechanical strength

Question 24

What does ground substance consist of?

Answer 24

proteoglycans
glycoproteins
phospholipids
water

Question 25

Composition + properties of proteoglycans

Answer 25

COMPOSITION: core protein + long unbranched polysaccharide chain PROPERTIES: highly polar water binding can act as lubricant/shock absorber

Question 26

Composition of glycoproteins

Answer 26

conjugated proteins | + 1 or more short, irregular saccharide side chains

Question 27

How are collagen fibres formed

Answer 27

1. tropocollagen secreted into ECM | 2. tropocollagen polymerises to form collagen - forms crosslinks

Question 28

What is tropocollagen?

Answer 28

3 alpha polypeptide chains bound together to form collagen

Question 29

Composition of collagen

Answer 29

33% glysine 10% hydroxyproline 0.5% hydroxylysine 66% AA - ie, glysine, alanine, proline

Question 30

What property does a high proline + hydroxyproline content lead to?

Answer 30

stiffness of the chain | - as there is a loss of free rotation

Question 31

Properties of collagen

Answer 31

basic hydrophilic - polar/soluble more crosslinks = less soluble

Question 32

How are collagen fibres arranged in areas bearing compressive loads?

Answer 32

in a lattice - lattice arrangement = tissue can stretch to some extent = strength + flexibility

Question 33

How are collagen fibres arranged in areas bearing tensional loads?

Answer 33

longitudinal arrangement

Question 34

How many types of collagen are there and where would they be found?

Answer 34

Type 1: in every CT Type 2: cartilage vitreous body of the eye Type 3: reticular fibres healing wounds smooth muscle Type 4: basement membrane bone + dentine (small amounts) Type 5: tendons bone + dentine + dental pulp (small amounts)

Question 35

What happens to the bonds in collagen with age?

Answer 35

weak bonds become strong covalent bonds = mechanical strength increases = becomes more brittle (eg, skin, bones)

Question 36

What forms elastin?

Answer 36

4 polypeptide chains | connected by high number of crosslinks

Question 37

Properties of elastin

Answer 37

stable elastic (stretch + recoil) insoluble

Question 38

Elastin contains a high number of _(a)_ residues ie, gly, ala, val, leu Elastin contains little/no _(b)_ residues ie, low hydroxyproline, no hydroxylysine Therefore, it is _(c)_philic

Answer 38

(a) non-polar (b) polar (c) lipo Elastin contains a high number of non-polar residues ie, gly, ala, val, leu Elastin contains little/no polar residues ie, low hydroxyproline, no hydroxylysine Therefore, it is lipophilic

Question 39

Function of elastin

Answer 39

contributes to elasticity of tissues

Question 40

Which dental structures can elastin be found in?

Answer 40

dentine dental pulp periodontal ligament bone

Question 41

Function of ground substance

Answer 41

1. provides unstructured filling space between cells + fibres 2. plays a role in mineralisation 3. holds water 4. provides environment for laying down/maturing proteins fibres during tissue development + turnover 5. biological function (eg, cell migration)

Question 42

Which dental structures are CT found in?

Answer 42

``` oral mucosa PDL alveolar bone cementum dentine dental pulp ```