Inflammation

Question 1

What are the five cardinal signs of inflammation?

Answer 1

1. Redness (rubor)
2. Heat (calor)
3. Swelling (tumour)
4. Pain (dolor)
5. Loss of function (functio leasa)

Question 2

What are the four phases of inflammation? Give a brief description of each.

Answer 2

1. Initiation: results in acute inflammation, rapid flooding of injured tissue with fluid, coagulation factors, cytokines, chemokines, platelets and inflammatory cells.
2. Amplification: additional leukocytes and macrophages recruited to area.
3. Destruction: inciting agents phagocytised and enzymatic/nonenxymatic processes reduces/eliminates foreign material. Damaged tissue is removed.
4. Termination: of the inflammatory response is mediated by anti-inflammatory mechanisms that limit tissue damage.
   5.

Question 3

What are the vascular events that occur during acute inflammation?

Answer 3

1. Transient vasoconstriction of arterioles
2. Vasodilation of precapillary arterioles occurs under the influence of nitric oxide (NO), histamine and other soluble agents.
3. An increase in the permeability of the endothelial cell barrier results in edema. Disruption of this barrier function is a hallmark of acute inflammation.
4. Intravascular stimulation of platelets and inflammatory cells, together with the release of soluble mediators produced at sites of injury.

Question 4

Define edema.

Answer 4

Edema is the accumulation of fluid within the extravascular compartment and interstitial tissues.

Question 5

Define transudate.

Answer 5

A transudate is edema fluid with a low protein content (specific gravity < 1.015).

• Transudates tend to occur in noninflammatory conditions in which the endothelial barrier remains intact and prevents the loss of large molecules from the vasculature.

Question 6

Define exudate.

Answer 6

An exudate is edema fluid with a high protein concentration (specific gravity > 1.015), which frequently contains inflammatory cells.

• Exudates are observed early in acute inflammatory reactions and are produced by mild injuries such as sunburn or traumatic blisters.

Question 7

Define serous exudate.

Answer 7

A serous exudate, or effusion, has a yellow, straw-like color and is characterized by the absence of a prominent cellular response.

Question 8

Define fibrinous exudate.

Answer 8

A fibrinous exudate contains large amounts of fibrin as a result of activation of the coagulation system.

Question 9

Define purulent exudate.

Answer 9

A purulent exudate or effusion contains prominent cellular components.

• It is frequently associated with pathologic conditions such as pyogenic bacterial infections in which the predominant cell type is the polymorphonuclear neutrophil (PMN).

Question 10

What are the three major enzyme cascades of the immune system?

Answer 10

1. The coagulation cascade
2. Kinin generation
3. Complement system

Question 11

Plasma contains elements of three major enzyme pathways, name these pathways.

Answer 11

1. The coagulation system and fibrinolytic system
2. Kinin generation
3. The complement system

Question 12

What is Hageman factor, how is it activated, and what does it do?

Answer 12

• Hageman factor is the name for clotting factor XII.
• It is generated in the plasma and is activated when exposed to negatively charged surfaces; basement membranes, proteolytic enzymes, bacterial lipopolysaccharides (LPS) and foreign materials.
• This factor triggers the activation of additional protease systems that are important in inflammation; coagulation system, fibrinolytic system, generation of kallikrein, activation of alternate complement pathway.

Question 13

What are kinins and what do they do? Give an example.

Answer 13

• Kinins are potent inflammatory agents formed in plasma and tissue by the action of serine protease kallikreins on specific plasma glycoproteins (kininogens).
• Kinins amplify the inflammatory response by stimulating local tissue cells and inflammatory cells to generate additional mediators; prostanoids, cytokines, and NO.
• Bradykinin and related peptides regulate multiple physiologic processes including blood pressure, contraction and relaxation of smooth muscle, plasma extravasation, cell migration, inflammatoy cell activation and inflammatory-mediated pain responses.

Question 14

What is the complement system?

Answer 14

• The complement system comprises a group of proteins found in plasma and on cell surfaces, whose primary function is defense against microbes.

Question 15

The complement system contains anaphylatoxins, opsonins, and proinflammatory molecules. What do each of these do and give examples of each.

Answer 15

1. Anaphylatoxins (C3a, C4a, C5a): proinflammatory molecules that mediate smooth muscle contraction and increase vascular permeability.
2. Opsonins (C3, iC3): bacterial opsonisation is the process by which a specific molecule (e.g. C3b) binds to the surface of a bacterium, enhancing phagocytosis by enabling receptors on the cell membranes of phagocytes (e.g. C3b receptor) to recognise and bind the opsonised bacterium.
3. Proinflammatory molecules (MAC,C5a): these chemotactic factors also (1) activate leukocytes and tissue cells to generate oxidants and cytokines and (2) induce degranulation of mast cells and basophils.