Acute and Chronic Inflammation

Question 1

What are the 3 physiological roles of inflammation?

Answer 1

Elimination of harmful agents (microbes, toxins)
Elimination of necrotic cells (damaged/dying cells)
Initiation of the healing process

Question 2

What could cause inflammation to injure normal tissues?

Answer 2

strong response (severe infection)
prolonged response (recurrent infection)
inappropriate response (self-antigens in autoimmune disease)

Question 3

What are leukocytes?

Answer 3

white blood cells

Question 4

List the types of phagocytes

Answer 4

neutrophils, mast cells,
(mononuclear) -> macrophages, monocytes, dendritic cells

Question 5

List the types of granulocytes

Answer 5

neutrophils, eosinophils, basophils, mast cells

Question 6

List the types of lymphocytes

Answer 6

B cells, T cells, NK cells

Question 7

List the characteristics of acute inflammation

Answer 7

Rapid Onset & short duration (mins to days)
Exudation: accumulation of fluid & plasma proteins (cause of swelling)
Accumulation of neutrophils
TNF, IL-1, Chemokines

Question 8

List the characteristics of chronic inflammation

Answer 8

• Insidious & longer duration (months to years)
• Effects:
  Tissue destruction by inflammatory cells
  Scarring caused by vascular proliferation & fibrosis
• Influx of lymphocytes & macrophages
• Synergistic stimulation:
  Interferon-γ (IFN-γ) by T cells
  Interleukin-12 (IL-12) by macrophages

Question 9

List the events that occur during the acute inflammatory response

Answer 9

• Phagocytes in tissues recognize offending agents and liberate chemical mediators of inflammation.
• Vasodilation: Chemical mediators widen blood vessels and increase their permeability in the vicinity.
• Leukocyte recruitment: Plasma and circulating leukocytes diffuse to the location of the offending agents.
• Phagocytosis: Activated leukocytes remove the offending agents.
• Leukocytes produce signaling molecules that suppress inflammation (e.g. lipoxins).
• Cell proliferation: The damaged tissue is repaired.

Question 10

What are the 5 classic signs of acute inflammation?

Answer 10

Heat, redness, swelling, pain, loss of function

Question 11

What are thee 2 component / stages of inflammation?

Answer 11

Vascular stage & Cellular stage

Question 12

What 2 things occur during the vascular stage of the acute inflammatory response?

Answer 12

Vasodilation & increased (vascular) permeability

Question 13

What are the effects of vasodilation during the vascular stage of the acute inflammatory response?

Answer 13

Decreased fluid velocity
Increased viscosity (thicker blood)
Margination: increased leukocyte settling along the inner surface of blood vessels

Question 14

What are the effects of increased (vascular) permeability during the vascular stage of the acute inflammatory response?

Answer 14

• Gaps due to endothelial contraction
• Transcytosis (increased fluid flow through endothelial injury)
• Leakage from new blood vessels that form at the site of injury

Sometimes:
- There is direct endothelial injury
- Leukocyte-dependent endothelial cell damage / death due to release of toxic mediators by leukocytes

Question 15

What 2 things occur during the cellular stage of the acute inflammatory response?

Answer 15

Leukocyte recruitment
Phagocytosis

Question 16

List the sequence of events in the Leukocyte recruitment step of the cellular stage of acute inflammation

Answer 16

Margination
Loose attachment & rolling (via selectins)
Adhesion (via integrins)
Transmigration
Chemotaxis

Question 17

Define chemotaxis

Answer 17

the movement of an organism or entity in response to a chemical stimulus

Question 18

What do immune cells recognize for Chemotaxis in acute inflammation?

Answer 18

Bacterial products
Chemokines
Complement system
Leukotriene B4

Question 19

List the sequence of events in the Phagocytosis step of the cellular stage of acute inflammation

Answer 19

Recognition (direct & indirect)
Engulfment
Intracellular killing

Question 20

Describe “direct recognition”

Answer 20

microbes recognized via pattern recognition receptors: TLRs & Mannose receptors

Question 21

What do TLRs recognize during “direct recognition”?

Answer 21

LPS, flagellin, etc.

Question 22

What do mannose receptors recognize during “direct recognition”?

Answer 22

sugars (mannose) from glycosylation by bacterial cells

Question 23

Describe “indirect recognition”

Answer 23

recognition via opsonins
Opsonization
Specific receptors recognize opsonins & swallow the coated bacteria

Question 24

What are examples of opsonins in “indirect recognition”?

Answer 24

IgG, C3b, and collectins
from the complement system

Question 25

What is opsonization?

Answer 25

Coating of the foreign body & dead cells

Question 26

List the sequence of events in the Engulfment step of the cellular stage of acute inflammation

Answer 26

receptor-mediated endocytosis: pseudopods extend around foreign body and form a phagosome

Question 27

List the sequence of events in the Intercellular Killing step of the cellular stage of acute inflammation

Answer 27

• Fusion of the phagosome with a lysosome (phagolysosome)
• Lysosomal degradation (digestive enzymes and defensins)
• Oxidative burst: Release of toxic nitrogen and oxygen compounds

Question 28

What toxic nitrogen & nitrogen compounds are released during an oxidative burst?

Answer 28

Hydrogen peroxide (H2O2)
Hypochlorous radical (HOCl)
Nitrous Oxide (NO)