Lecture 19 How the Body Responds to Injury

Question 1

What are the key cardinal signs of inflammation

Answer 1

• Heat
• Swelling
• Pain
• Redness

Question 2

Which cells are the first to respond during inflammation

Answer 2

Neutrophiles

Question 3

What three key things occur during acute inflammation?

Answer 3

1) Vascular Dilation
2) Increased vascular permeability and extravasation of fluid
3) Emigration of leukocytes, primarily neutrophile polymorphs

Question 4

What occurs during vasodilation?

Answer 4

1) Vascular smooth muscle relaxes rapidly mediated by histamine and nitric oxide
2) Increased amount of blood but slower flow in the area of vasodilatation
3) This results in stasis of blood and an increase in hydrostatic pressure beyond normal levels - oedema

Question 5

What occurs in vascular permeability?

Answer 5

Histamine and Nitric Oxide also activate endothelial cells causing

• contraction of endothelium
• vascular permeability increases
• cells, proteins, mediators leak
• increase in tissue osmotic pressure
• more oedema

Question 6

What occurs in cellular exudate?

Answer 6

Phagocytic leukocytes (mainly neutrophils but also macrophages) leave the vasculature in the following 3 steps:

1) Margination and rolling along the vessel blood wall
2) Adhesion to the activated endothelium
3) Emigration through the vessel wall into the surrounding tissues

Question 7

What is the mediator for vasodilation?

Answer 7

Histamine, NO and prostaglandins

Question 8

What are the mediators for increased vascular permeability?

Answer 8

Histamine, Complement C3a and C5a

Question 9

What are the mediators for chemotaxis and leucocyte recruitment?

Answer 9

TNF, IL-1, Complement C3a and C5a

Question 10

What are the mediators for fever?

Answer 10

TNF, IL-1 and Prostoglandins

Question 11

What are the mediators for pain

Answer 11

Prostoglandins and Bradykinin

Question 12

What are the mediators for tissue and cell damage

Answer 12

Lysosomal Enzymes from Leukocytes

Question 13

What is an abcess?

Answer 13

Collection of pus with lots of neutrophiles

Question 14

What are the three possible outcomes of acute inflammation

Answer 14

1) Complete resolution
2) Healing by Scarring
3) Progression to Chronic Inflammation

Question 15

What causes chronic inflammation and what is its consequences?

Answer 15

Chronic Inflammation is a consequence of acute inflammation

1) Persistent infections (e.g. viral or fungal infections)
2) Inability to heal (e.g. chronic peptic ulcer of the stomach)
3) Immune mediated inflammatory diseases (e.g. Crohn’s disease, glomerulonephritis)
4) Prolonged exposure to toxic agents (e.g. silicosis of the lung)

Question 16

What is granulomatous?

Answer 16

• A distinctive pattern of chronic inflammation
• A granuloma is a collection of activated epithelioid (epithelium-like) macrophages
• It may be surrounded by lymphocytes or not (naked granulomas e.g. in sarcoidosis)
• It may show central necrosis (necrotizing granuloma e.g. mycobacterium) or not (non-necrotizing granuloma)