Healing and Repair

Question 1

body cells are of 3 types in relation to their ability to regenerate

Answer 1

1. labile eg epithelial cells
2. stable eg hepatocytes
3. permanent eg nerve, skeletal and cardiac cells

Question 2

what are the types of wound healing intention

Answer 2

1. primary - narrow
2. secondary - wide

Question 3

what are the stages of wound healing

Answer 3

1. haemostasis and inflammatory phase
2. proliferation/ migratory phase
3. remodelling/ maturation phase

Question 4

summarise coagulation and inflammation stage

Answer 4

1. initial blood loss, clot formation
2. inflammatory response - vasidilation
3. plasma - tissue bring neutrophils/ macrophages

Question 5

which types of cells proliferate and migrate

Answer 5

1. fibroblasts
2. endothelium (migrate in arcs - angiogenesis)
3. epithelium (migrate in sheets)

Question 6

the cells at the edges of damaged skin respond to fibronectin - what is it

Answer 6

• insoluble glycoprotein
• a general cell adhesion molecule

Question 7

what role do myofibroblasts (from fibroblasts) play in wound healing

Answer 7

initiate early wound contraction

Question 8

why is angiogenesis necessary

Answer 8

1. provides O2
2. removes metabolic and repair waste

Question 9

what does granulation tissue consist of

Answer 9

• newly formed capillaries
• fibroblasts elaborating connective tissue
• many macrophages

Question 10

granulation tissue has 3 properties

Answer 10

1. bleeds freely
2. insensitive to pain
3. resistant to infection

Question 11

what is the process of forming avascular tissue from granulation tissue

Answer 11

cicatrisation

Question 12

which growth factors are involved in the remodelling stage (5)

Answer 12

• PDGF: platelet derived growth factor
• TGF: transforming growth factor
• EGF: epidermal growth factor
• IGF: insulin-like growth factor
• IL-1: interleukin-1

Question 13

key features of venous ulcers

Answer 13

1. most common type of ulcer affecting the lower extremities
2. caused by venous stasis
3. haemosiderosis pigmentation
4. usually near medial malleolus
5. oesematous and indurated lower extremity
6. shallow, not too painful, lots of exudate

Question 14

which cells are critical in bone healing (3)

Answer 14

1. osteoblasts
2. osteoclasts
3. osteocytes

Question 15

what are the stages of bone healing

Answer 15

1. inflammation
2. repair and formation of soft callus (provisional); hard callus
3. bone remodelling

Question 16

bone healing: stage 1: inflammation (4)

Answer 16

1. bleeding from bone and tissue
2. acute inflammation and oedema
3. osteocytes lose their nutrition and die
4. macrophages, lysosomes clear debris

Question 17

bone healing: stage 2: repair and formation of soft callus (4)

Answer 17

1. fibrin mesh acts as a scaffols for healing
2. granulation tissue is basis for new bone
3. fibroblasts and chondrocytes invade granulation tissue
4. fracture stiffens as fibro-cartilagenous callus forms
5. new bone cannot be seen on x-rays
6. last 3 weeks or more

Question 18

bone healing: stage 2: formation of hard callus

Answer 18

1. between 4-8 weeks
2. fusiform mass of callus immobilises fragments
3. new bone becomes mineralised (ossification)
4. can be seen on x-rays

Question 19

bone healing: stage 3: remodelling

Answer 19

1. 8-12 weeks
2. deformities are corrected
3. can last for several years

Question 20

summary of bone healing (6)

Answer 20

1. heamotoma
2. granulation
3. capillaries
4. collagen fibres
5. bony callus formation
6. bony callus remodelled