Theme 4b Inflammation

Question 1

What are the steps of inflammation?

Answer 1

1. Tissue damage and bacteria cause resident sentinel cells to release chemoattractants and vasoactive factors that trigger a local increase in blood flow and capillary permeability
2. The permeable capillaries allow an influx of fluid or exudate, which contains complement, and antimicrobial proteins.
3. Neutrophils and other phagocytes migrate to site of inflammation via chemotaxis.
4. Phagocytes extravasate into the the damaged/infected region and destroy bacteria.

Question 2

What are the symptoms of acute inflammation?

Answer 2

Rubor (redness), Calor (heat), Tumor (swelling), Dolor (pain), Loss of function (pain leads to neurological reflex).

Question 3

What is the purpose of acute inflammation?

Answer 3

• Delivery of leukocytes & plasma proteins to the site of injury
• Elimination of pathogens
• Triggering of acquired immunity & systemic responses
• Initiation of tissue repair.

Question 4

What are some triggers of inflammation?

Answer 4

• Infections
  -Trauma
• Physical and chemical injury
• Tissue necrosis
• Immune reactions

Question 5

What happens to fibroblasts during inflammation?

Answer 5

They proliferate and synthesize collagen to make an extracellular matrix required for tissue repair.

Question 6

What happens to the vascular endothelium during acute inflammation?

Answer 6

• Increased expression of leukocyte adhesion molecules (E-selectin/ ICAMs).
• Produce IL-1 chemokines.
• Increase procoagulant and decrease anticoagulant activity.

Question 7

How do inflammation stimulants change blood flow?

Answer 7

• Vasodilation (widening of blood vessels)
• Vascular stasis (slowing of the blood in the blood stream)

Question 8

What are Eicosinoids?
Give two example groups involved in inflammation.
What does each group do?

Answer 8

• Eicosinoids are signaling molecules made of fatty acids
• Prostaglandins and Leukotrienes as two examples which are produced from macrophages, platelets and endothelium.
• Prostaglandins promote vascular permeability, platelet aggregation and increased pain sensitivity.
• Leukotrienes promote vascular permeability and chemotaxis

Question 9

What are four soluble mediators involved in inflammation?

Answer 9

• Complement system - lipid mediator release from basophils, Eosinophils (BMP) and neutrophils (histamine)
• The kinin system - vasodilation
• The coagulation system - clotting
• The fibrinolysis system- mediate coagulation and inflammation.

Question 10

Define fever
what causes it?

Answer 10

An increase in body temperature above the normal range (36.5- 37.5 C)
pyrogens like IL-1, IL-6 and TNF-alpha

Question 11

What is leukocytosis? What is the most common type?

Answer 11

When the WBC count is above the greater than normal range. Neutrophilia is the most common type of leukocytosis caused by IL-1 and TNF causing the bone marrow to release more of these cells.

Question 12

How is acute inflammation terminated?

Answer 12

• short half-lifes of inflammatory mediators like C5a/C3a
• production and release of anti-inflammatory cytokines (IL-10 and TGF-β)
• Apoptosis of pro-inflammatory cells like neutrophils (10hrs in circulation, 1-2 days in tissues)
• Desensitization of receptors (prostaglandin receptors)

Question 13

What are common causes of chronic inflammation?

Answer 13

• Chronic infection or ineffectual clearance of pathogens
• Chronic physical damage to tissues can cause them to perpetually release DAMPs that induce inflammatory mediators.
• Obesity, due to the release of cytokines like IL-6 and TNF-alpha
• Autoimmune disorders (arthritis)
• Diabetes with cytokines like IL-6 or TNF-alpha inhibiting downstream effects at the insulin receptor.

Question 14

What are some consequences of chronic inflammation?

Answer 14

• Excessive tissue scarring (fibrosis) which can lead to organ dysfuntions which can complicate into tumors or autoimmune disorders
• May cause obesity or type-2 diabetes.