Pathology of Inflammation

Question 1

What is inflammation a response to?

Answer 1

Tissue injury

Question 2

What are the causes of inflammation?

Answer 2

• Pathogens
• Trauma/radiation
• Chemical/organic poisons
• Immunological agents
• Tissue necrosis and hypersensitivity

Question 3

What does -itis suggest?

Answer 3

• Acute inflammation of a specific tissue

Question 4

What are the cardinal signs of inflammation?

Answer 4

• Redness and heat caused by increased blood flow
• Swelling caused by increased vascular permeability and exudation
• Pain due to release of bradykinin and PGE2

Question 5

Outline the exact steps involved in response to tissue injury.

Answer 5

• Vascular phase of increased flow
• Exudate formation
• Neutrophil infiltration of tissue
• Bacterial phagocytosis
• Resolution and organisation

Question 6

What are the steps of the vascular phase of acute inflammation?

Answer 6

• Alteration in blood flow to injury site
• Increase in vascular permeability

Question 7

Describe the first step of blood flow alteration in the vascular phase.

Answer 7

• Transient vasoconstriction - mediated by arteriolar smooth muscle contraction.
• Short-lived reduction in blood flow to site of injury.

Question 8

Describe endothelial cell contraction.

Answer 8

• Occurs predominantly in venules
• Response to inflammatory mediators e.g histamines, bradykinins
• Rapidly occurring and short-lived

Question 9

Describe the second step of blood flow alteration in the vascular phase.

Answer 9

• VASODILATION
• Relaxation of arteriolar smooth muscle - increase in permeability and blood flow to nearby tissues
• Sustained and lasts for many hours

Question 10

Describe blood pressure in vessels during the vascular response.

Answer 10

• NORMALLY - balanced oncotic and hydrostatic pressures
• ACUTE INFLAMMATION - disturbed pressures as a result of increased permeability

Question 11

What is the difference between transudate and exudate?

Answer 11

• TRANSUDATE - low protein content
• EXUDATE - high protein content e.g containing antibodies, complement proteins

Question 12

Define oedema.

Answer 12

• Presence of excess fluid within extravascular space and may be exudate/transudate

Question 13

Define pus.

Answer 13

• Protein-rich exudate
• Contains dead/dying bacteria and neutrophils

Question 14

Describe the changes in vascular permeability that occurs during endothelial cell damage.

Answer 14

• Seen after burns and bacterial infections
• Delay between time of injury and leakage of exudate
• Leakage sustained until occlusion/repair of vessels

Question 14

What is the intended outcome of the vascular phase?

Answer 14

• Exudate formation and oedema
• Reduced blood flow and stasis