Inflammation and repair

Question 1

5 signs of acute inflammation

Answer 1

1. Heat
2. Redness
3. Swelling (oedema)
4. Pain
5. Loss of function

Question 2

Inflammation

Answer 2

• physiological response to tissue injury
• the pattern of events is similar
• acute inflammation
  + initial, often transient tissue response
• chronic inflammation
  + prolonged tissue reponse

Question 3

Acute inflammation: vascular response

Answer 3

• release of inflammatory mediators
  + causing hyperaemia (due to vasodilation)
  + causing oedema (due to increased vascular
  permeability and raised hydrostatic pressure driving
  fluid and proteins into the tissue = exudate)

Question 4

Acute inflammation: cellular response

Answer 4

• involves leucocytes - mainly neutrophils
  (monocytes/macrophages arrive later)
• recruitment into extravascular tissue involves:
  
  1. Margination, rolling and adhesion of leucocytes
  2. Diapedesis (movement through endothelium)
  3. Migration in tissues via chemotaxis (move along a
     chemical gradient)
  4. Phagocytosis (engulfment and dehydration)

Question 5

Acute inflammation - outcomes

Answer 5

• resolution/regeneration
  + restoration of normal structure and function
• organisation (scarring or fibrosis)
  + replacement of normal tissue by deposition of collagen fibres
  + formation of scar
  + loss of normal structure and function
• chronic inflammation

Question 6

Factors that influence repair

Answer 6

• tissue type
  + some tissues have limited ability to regenerate
• severity or location of the injury
• factors that can impair repair

Question 7

Acute inflammation: resolution

Answer 7

• healing without scarring
• restoration of structure and function
  + proliferation of surviving cells (some macrophages,
  fibroblasts)

Question 8

Acute inflammation: organisation

Answer 8

• organisation may occur following acute inflammation
  + always occur in chronic inflammation
• granulation tissue forms
  + macrophages remove dead cells
  + fibroblasts replicate and secrete collagen protein
  + new vessels grow by angiogenesis
• once new matrix is formed, fibroblasts and
  macrophages leave, the new vessels die by apoptosis
• mature collagen scar persists
  + tissue function lost
  + scar contracts with time

Question 9

Chronic inflammation

Answer 9

• inflammatory process in which lymphocytes, plasma
  cells and macrophages predominate
• lymphocytes - part of the acquired immune system
  + T cells
  + B cells -> plasma cells -> antibodies
  + T and B cells promote inflammation
• involves continued injury, inflammation and repeated
  attempts to repair
• may be extensive tissue necrosis
• repair occurs by organisation

Question 10

Chronic inflammation: outcomes

Answer 10

- associated with many common chronic diseases
   \+ rheumatoid arthritis
   \+ atherosclerosis
   \+ cancer
   \+ neurodegenerative disorders