Lecture 4 Tissue repair and injury

Question 1

Define regeneration

Answer 1

Complete reconstitution

Question 2

What is needed for regeneration?

Answer 2

Tissue with high proliferation, viable stem cells and intact connective tissue (scaffolding)

Question 3

Define repair

Answer 3

Combination of regeneration and scar formaiton

Question 4

What does repair rely on?

Answer 4

Capacity to regenerate, extent of injury and extent of scaring.

Question 5

Examples of regeneration

Answer 5

Liver regeneration after partial hepatectomy, superficial skin wounds, resorption of exudate in lobar pneumonia.

Question 6

Examples of repair

Answer 6

Deep excisional wounds, myocarium infaction

Question 7

Examples of fibrosis

Answer 7

Chronic inflam diseases, cirrhosis, pancreatitis, pulmonary fibrosis.

Question 8

2 limited examples of true regeneration?

Answer 8

epithelium following superficial skin injury & bone after fracture.

Question 9

Example of hypertrophy to compensate

Answer 9

Nephrons following nephrectomy

Question 10

Example of hyperplasia to compensate

Answer 10

Hepatocytes following partial hepatectomy

Question 11

Fibro-proliferative response is when

Answer 11

Deposition of collagen and ECM component (scar). “patches” tissue.

Question 12

Sequence of healing 5 steps?

Answer 12

Inflam, angiogenesis, migration & prolife of parenchymal cells &fibroblasts, scar, connective tissueremodelling.

Question 13

When healing a larger scab what happens to the inflammation?

Answer 13

More nacrotic debris, exudate and fibrin to remove -> inflam more intense

Question 14

Define granulation tissue

Answer 14

New connective tissue with tiny blood vessels

Question 15

What does a larger amount of granulation tissue mean?

Answer 15

a larger defect. Involves wound contraction

Question 16

What local factors affect wound healing?

Answer 16

Size, location (how well its vascularised), type (infectious/necrotic/traumatic), infections.

Question 17

What systemic factors affect would healing?

Answer 17

Nutritional status, metabolic status (diabetes), circulatory/vascular status, hormones (glucocorticoids).

Question 18

What can complicate repair?

Answer 18

Deficient scar formation -> wound dehiscence (wound ruptures along surgical line)

Question 19

Excessive repair complications (3)

Answer 19

Excessive granulation tissue (proud flesh), excessive collagen accumulation (hypertrophic scar), Keloid.

Question 20

Define keloid

Answer 20

area of irregular fibrous tissue formed at the site of a scar or injury

Question 21

Repair complication - formation of contractures

Answer 21

Contracture of skin due to burn.