healing ad repair

Question 1

what is regeneration?

Answer 1

proliferation of cells and tissue to replace lost or damaged cells and tissue - normal structure restored

Question 2

what is repair?

Answer 2

response to injury involving regeneration and scar formation (fibrosis), normal structure permanently altered

Question 3

which outcome is seen as resolution, regeneration or repair ?

Answer 3

regeneration

Question 4

what are liable cells?

Answer 4

normal state is active cell division, rapid regeneration

Question 5

give an example of a liable cell?

Answer 5

oral keratinocyte

Question 6

what is a stable cell?

Answer 6

not normally dividing at significant rate, can undergo rapid proliferation in response to injury

Question 7

give an example of a stable cell?

Answer 7

oral fibroblast

Question 8

what is a permanent cell?

Answer 8

unable to divide or regenerate

Question 9

give an example of a permeant cell

Answer 9

nerve cell

Question 10

what are the 4 stages of wound healing?

Answer 10

1 haemostasis
2 inflammatory
3 proliferation
4 remodelling

Question 11

what does haemostasis refer to?

Answer 11

blood clotting

Question 12

what happens during the inflammatory phase of wound healing?

Answer 12

fibroblasts and macrophages accumulate, scab forms

Question 13

what happens during the proliferation phase of wound healing?

Answer 13

1st phase - vascular granulation tissue forms

2nd phase - fibrous granulation tissue forms

Question 14

what happens during the remodelling phase of wound healing?

Answer 14

freshly healed epidermis and dermis, re-epithelialisastion and maturation

Question 15

what fibrous protein pulls the wound together and provides tensile strength?

Answer 15

collagen

Question 16

what does healing by 1st intention refer to?

Answer 16

surgical incision

Question 17

what does healing by 2nd intention refer to?

Answer 17

dirty wound, larger scab, more inflammation due to necrotic debris, exudate and fibrin to remove, larger granulation tissue, invoke wound contraction

Question 18

what is angiogenesis ?

Answer 18

growth of new BVs from existing vasculature

Question 19

what are the 2 mechanisms of angiogenesis and how do they work?

Answer 19

• sprouting ( new BV from existing)

- intussusceptive ( splitting angiogenesis)

Question 20

what is angiogenesis controlled by?

Answer 20

vascular endothelial growth factor (VEGF)

Question 21

which two growth factors inhibit and promote cell growth and differentiation?

Answer 21

• cytokines

- hormones

Question 22

give some functions of growth factors

Answer 22

• promote cell survival
• locomotion
• contractility
• differentiation
• angiogenesis
• activate signal transduction pathways

Question 23

which cells produce collagen?

Answer 23

fibroblasts

Question 24

what are the 4 stages of fracture healing?

Answer 24

• reactive phase
• reparative (regenerative) phase
• bonny callous formation
• remodelling phase

Question 25

what happens during the reactive phase of fracture healing?

Answer 25

• blood clot forms (haematoma)

- macrophages scavenge debris producing inflammatory agents

Question 26

what happens during the reparative phase of fracture healing?

Answer 26

• inflammation triggers growth of new BVs
• chondrocytes secrete collagen and osteoblasts start producing spongy bone
• soft callus is formed

Question 27

what happens during the bonny callous phase of fracture healing?

Answer 27

• woven bone replaces soft callous to create hard callous round the broken bone fragments

Question 28

what is fibrosis?

Answer 28

formation of scar tissue- extensive deposition of collagen & formation of excess fibrous connective tissue

Question 29

fibrosis occurs in response to what?

Answer 29

chronic inflammation

Question 30

which immune cells initiate fibrosis and which growth factor do they produce?

Answer 30

M2 macrophages - releasing TGF-beta

Question 31

during which phase of fracture healing is fracture callus produced?

Answer 31

regenerative

Question 32

granulation tissue formation occurs during which stage of wound healing?

Answer 32

proliferation

Question 33

fibrosis is characterised by the extensive deposition of which substance in tissues?

Answer 33

collagen

Question 34

what happens during the remodelling phase of fracture healing?

Answer 34

• osteoclasts and osteoblasts remodel the bone, replacing hard callus with mature lamellar bone

Question 35

during which stage of wound healing does angiogenesis occur?

Answer 35

proliferative phase