CP3: Repair of tissue damage

Question 1

What is always an outcome of tissue loss and destruction?

Answer 1

Inflammation occurs in all cases

Question 2

What are the 4 stages of tissue repair?

Answer 2

• Hemostasis
• Inflammation
• Proliferation
• Remodelling

Question 3

Define Regeneration

Answer 3

Regeneration is the replacement of injured cells with cells of the same type

Question 4

Define Resolution

Answer 4

Resolution is the complete return to normal structure and function after injury

Question 5

Define Restitution

Answer 5

Restitution is return to normality due to a combination of regeneration and resolution

Question 6

Define Repair

Answer 6

Repair is the replacement of lost tissue by fibrous (scar) tissue

Question 7

Wound healing process

Answer 7

• Wound with escape of blood
• haemostasis/clotting
• inflammation
• macrophages remove debris
• cells regenerate if possible
• microvessels grow in/angiogenesis
• fibroblasts move in, proliferate and lay down collagen
• scar

Question 8

What is a labile cell?

Answer 8

Cells continue to proliferate throughout life to replace those that are constantly being destroyed

Question 9

What is a stable cell?

Answer 9

Cells that turn over at a low level under normal circumstances but which are capable of rapid replication if required

Question 10

What is a permanent cell?

Answer 10

Either incapable of mitotic division or organised proliferation

Question 11

Examples of Labile cells

Answer 11

• Skin
• Gut mucosa
• Bone marrow

Question 12

Examples of stable cells

Answer 12

• Kidney
• Liver
• Endocrine glands
• Bone

Question 13

Examples of permanent cells

Answer 13

• Cardiac muscle
• Neurones
• Striated/skeletal muscle

Question 14

When can’t stable/labile cells not regenerate?

Answer 14

If the architectural structure is compromised

Question 15

What 3 tissues can regenerate all constituents

Answer 15

• Liver
• Bone
• Bone marrow

Question 16

What are adult stem cells?

Answer 16

Make cells in certain niches like skin, GI tract, liver, bone marrow

Question 17

What do fibroblasts synthesise?

Answer 17

Synthesise extracellular matrix and collagen

Question 18

What is the role of macrophages? (4)

Answer 18

• Clear debris
• Secrete growth factors
• Stimulate endothelial cells
• Stimulate fibroblasts

Question 19

Steps in fracture healing

Answer 19

– Cartilage formed in granulation tissue from chondrocytes
– Bridges gap (provisional callus)
– Calcification and ossification by osteoblasts (fibrocartilagenous callus then bony callus)
– remodelling by osteoclasts/blasts
– woven bone becomes lamellar (as before)
– only situation where granulation tissue leads to regeneration, every other time repair with fibrosis

Question 20

Systemic factors that affect healing? (6)

Answer 20

– Age
– Nutrition
– Diabetes mellitus
– Steroids
– Chronic illness eg renal failure
– Haematological disorder

Question 21

Local factors that affect healing? (7)

Answer 21

– Infection
– Foreign material embedded in wound
– Blood supply
– Type of tissue
– Extent of injury 
– Mobility
– Radiation