PMI03-2024

Question 1

What is meant by the term regeneration?

Answer 1

Replacement of lost/damaged tissue by that of a similar type, derived from the proliferation of surrounding undamaged cells

Question 2

What is meant by the term resolution?

Answer 2

Return to original morphological and functional state with little damage

Question 3

Give an example of a tissue that can undergo regeneration.

Answer 3

Liver

Blood

Question 4

What is meant by the term repair?

Answer 4

Replacement of lost/damaged tissue by granulation tissue which later matures into either fibrous scar tissue or other tissue

Question 5

What are the two types of repair processes and which is helpful?

Answer 5

Healing = helpful repair

Fibrosis = unhelpful

Question 6

What is the term healing generally used for?

Answer 6

Small skin wounds

Question 7

When does healing by primary intention occur?

Answer 7

When wound edges are in close apposition

Question 8

When does healing by secondary intention occur?

Answer 8

When wound is more extensive and wound edges are widely separated

Question 9

What is the key element of healing by primary intention?

Answer 9

Re-epithelialisation

Question 10

What are the stages in healing and when do they occur after injury?

Answer 10

1. Haemostasis ~1 hour
2. Inflammation ~48 hours
3. Re-epithelialisation ~1-3 days
4. Granulation tissue formation ~2-5 days
5. Maturation ~5 days

Question 11

What happens in the haemostasis step of healing?

Answer 11

Platelet plug and fibrin clot formation

Question 12

How can warfarin, aspirin or factor VIII deficiency affect wound healing?

Answer 12

Inhibits haemostasis so inhibits wound healing

Question 13

What is involved in the inflammation stage of healing?

Answer 13

Macrophage infiltration and debridement

Question 14

What is granulation tissue?

Answer 14

Loose cellular connective tissue with many plump synthetic fibroblasts, dilated, irregular blood vessels and inflammatory cells

Question 15

Describe the granulation tissue formation stage of wound healing.

Answer 15

Connective tissue component

Endothelial cell and fibroblast formation from wound edges give rise to new blood vessels

Blood vessels migrate out into wound area accompanied by fibroblasts and inflammatory cells to lay down collagen ECM

Question 16

Describe the re-epithelialisation stage of wound healing.

Answer 16

Epithelium component

Proliferation of basal epithelial cells adjacent to wound

Migration of basal epithelial cells across wound bed, under fibrin scab to restore epithelial continuity

Basal cells differentiate to reform stratified squamous epithelium

Question 17

What are traditional macrophage functions involved in wound healing?

Answer 17

Phagocytosis

Protease synthesis

Regulation of immune cell function

Growth factor production

Question 18

Give two examples of growth factors produced by macrophages which are involved in wound healing.

Answer 18

FGFs = fibroblast recruitment and activity

VEGF = endothelial cell recruitment and activity

Question 19

What systemic factors can influence wound healing?

Answer 19

Age

Nutritional status

Iatrogenic/medications

Pre-existing medical conditions

Question 20

What local factors can influence wound healing?

Answer 20

Blood supply

Infection

Persistent irritation

Poor wound stability

Poor apposition of wound edges

Direction of incision (Langers lines)

Ionising radiation

Question 21

What does wound dehiscence mean and what can it result in?

Answer 21

Re-opening of wound

Hernias

Question 22

What does contracture mean?

Answer 22

Normally elastic tissues are replaced by inelastic tissues (fibrosis) leading to rigidity

Question 23

What can exaggerated, hyperplastic wound healing responses cause?

Answer 23

Keloids

Hypertrophic scar formation

Question 24

Describe a keloid.

Answer 24

Sharply elevated, progressively enlarging scar

Characterised by formation of excessive amounts of collagen in the dermis during connective tissue repair

May spread beyond margins of original wound

Characteristically found in Afro-Caribbean populations

Question 25

What wound healing complications can affect the face/skin but not the oral mucosa?

Answer 25

Keloids and hypertrophic scarring

Marjolin ulcers

Question 26

What is the difference between hypertrophic scarring and keloids?

Answer 26

Hypertrophic scarring does not spread past wound margins and affects varied population groups

Question 27

Which cells are responsible for contraction/bring edges of wound closer together?

Answer 27

Myofibroblasts