Acute Inflammation

Question 1

Define inflammation

Answer 1

The response of living tissue to injury

Question 2

List some characteristics of acute inflammation

Answer 2

• stereotyped
• innate
• immediate
• short duration (few hours to a few days)
• limits damage
• controlled
• protective (but can cause local or systemic problems)

Question 3

What are the causes of acute inflammation?

Answer 3

• microbial infections (e.g. viruses)
• hypersensitivity reactions (e.g. parasites)
• physical agents (e.g. trauma, heat, cold)
• chemicals (e.g. corrosives, acids)
• tissue necrosis (e.g. is had mic infarction)

Question 4

What are the clinical signs of acute inflammation (5 cardinal signs)?

Answer 4

• Rubor (redness)
• Tumour (swelling)
• Dolor (pain)
• Calor (heat)
• Loss of function

Question 5

What are the two phases of acute inflammation?

Answer 5

1) Vascular phase

2) Cellular phase

Question 6

What happens during the vascular phase? (Inc. three steps)

Answer 6

• Changes in blood flow; accumulation of exudate
  1) Vasoconstriction = trap pathogens
  2) Vasodilation = heat and redness
  3) Increased permeability = fluid and cells can escape

Question 7

What is Starling’s law (not CVS)?

Answer 7

Movement of fluid due to the (im)balance between hydrostatic pressure and on oncotic pressure

Question 8

What is hydrostatic pressure?

Answer 8

Pressure exerted on vessel wall by fluid (draw fluid away)

Question 9

What is oncotic pressure?

Answer 9

Pressure exerted by proteins; draws fluid towards

Question 10

What are the two types of interstitial fluid?

Answer 10

• Exudate

- Transudate

Question 11

Describe Exudate

Answer 11

Protein rich fluid that delivers the proteins to area of injury (from increased permeability; occurs in inflammation)

Question 12

Describe transudate

Answer 12

Interstitial fluid without proteins from increased capillary hydrostatic pressure and reduced capillary oncotic pressure (occurs in heart failure, hepatic failure, renal failure)

Question 13

How is the vascular phase effective?

Answer 13

• interstitial fluid dilutes toxins
• delivery of proteins such as fibrin (mesh limits spread) and antibodies
• fluid drains to lymph nodes = stimulate adaptive response

Question 14

What happens during cellular phase?

Answer 14

Neutrophils are delivered to area of inflammation where they phagocytise pathogens

Question 15

How do neutrophils leave vessels?

Answer 15

1) Margination = goes to edge of endothelium
2) Rolling = weak bond formation (selectins)
3) Adhesion = binding tightly (integrins)
4) Emigration = diapedesis, escape vasculature

Question 16

Define chemotaxis

Answer 16

Movement along an increasing chemical gradient of chemoattractants (e.g. bacterial peptides, inflammatory mediators)

Question 17

How do neutrophils recognise correct material to phagocytose?

Answer 17

Opsonisation = toxin/pathogen covered in opsonins e.g. C3b

They have receptors for the opsonins on their surface

Question 18

What are the two killing mechanism of neutrophils?

Answer 18

• Oxygen dependent = ROS & RNS

- Oxygen independent = lysozyme, defensins, hydrolytic enzymes

Question 19

How is the cellular phase effective?

Answer 19

• removes pathogens and necrotic tissue

- releases inflammatory mediators (chemical messengers)

Question 20

What are the local complications of acute inflammation?

Answer 20

• swelling = compression of tubes such as airways
• exudate compressing on organs
• loss of fluid e.g. burns
• pain = muscle atrophy, psycho-social consequences

Question 21

What are detrimental systemic consequences of acute inflammation?

Answer 21

• fever = some mediators are pyrogens (e.g. prostaglandins, IL-1)
• septic shock = huge release of chemical mediators causes widespread vasodilation

Question 22

What are beneficial systemic consequences of acute inflammation?

Answer 22

• leucocytosis = increased production of white cells (level can be measured to monitor)
• acute phase response = malaise, reduced appetite to induce rest

Question 23

What are the 3 possibilities after acute inflammation?

Answer 23

1) Complete resolution
2) Repair connective tissue
3) Progression to chronic inflammation