Exam #1: Acute Inflammation II Flashcards

1
Q

Generally, how are organisms phagocytosed?

A

1) Recognition of the offending agent & activation of leukocytes
2) Engulfment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the mediators of recognition and attachment.

A
  • Mannose receptors= recognize mannose and fucose on microbial cell walls
  • Scavenger receptors
  • Opsonins= IgG & C3b
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the process of engulfment.

A

After a microbe has bound to a phagocyte receptor:

1) Pseudopods, or extensions of the cytoplasm, surround the object forming a phagosome
2) Phagosome that fuses with the lysosome, creating a phagolysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two systems for killing organisms?

A

Once the phagolysosome has formed, killing is mediated by two pathways:

1) Oxygen-dependent
2) Oxygen-independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the oxygen-dependent/ aerobic process for killing organisms?

A

Respiratory burst

1) Oxygen–>superoxide via NADPH oxidase
2) Superoxide–>Hydrogen peroxide via superoxide dismutase
3) Myelo-peroxidase from neutrophilic granules catalyzing reaction between Cl- & Hydrogen peroxide, forming hypochlorus acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What reaction is carried out by NADPH oxidase?

A

Oxygen–>Superoxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What reaction is carried out by Superoxide Dismutase?

A

Superoxide–>Hydrogen peroxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is myelo-peroxidase from? What reaction does it catalyze?

A

Neutrophils
CL- & H2O2–>HOCl

(Hypochlorous acid i.e. bleach)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the oxygen-independent mechanism for killing organisms.

A

The oxygen-independent mechanisms of killing include leukocyte granule proteins and enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is leukocyte activation?

A

Initiating secretion or production of cell surface proteins by leukocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the functional responses induced on leukocytes upon activation?

A

1) Production of arachidonic acid (AA) metabolites
2) Degranulation & secretion of lysosomal enzymes & activation of oxidative burst
3) Secretion of cytokines
4) Modulation of adhesion molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the general characteristics of inflammatory mediators.

A
  • Originate from plasma proteins or cells
  • Bind to specific receptors on target cells
  • Can stimulate the release of other mediators from target cells
  • Most are short lived
  • Most have the potential to cause harmful effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the vasoactive amines?

A

Histamine

Serotonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of the vasoactive amines?

A
  • ARTERIOLAR dilation (vasodilation)

- Increased permeability of POSTCAPILLARY VENULES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where do the vasoactive amines come from?

A

Stored in preformed granules of mast cells, basophils, and platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What causes the release of vasoactive amines from mast cells?

A
  • Trauma
  • Platelet aggregation
  • C3a, C4a, C5a
  • Neuropeptides
  • Cytokines
  • Histamine releasing proteins
  • IgE binding to mast cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Review the three pathways of complement activation.

A

1) Classic= binding of antigen- antibody complex to C1
2) Alternate= C3 directly activated by bacterial endotoxins, complex polysaccharides, & aggregated globulins
3) Lectin= C1 activation by mannose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the center of complement activation?

A

C3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of C3a, C4a, and C5a in imflammation?

A

Stimulate histamine release from mast cells leading to increased vascular permeability & vasodilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of C5a?

A
  • Chemotaxis of monocytes & granulocytes
  • Increases surface expression of leukocyte CAM
  • Activates LOX pathway in neutrophils & monocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of C3b?

A

Opsonization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of C5-9?

A

Membrane attack complex (MAC) that inserts into the lipid bilayer forming macropores tha ticnrease the cell permeability & leads to lysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is Hageman Factor?

A

Factor XII of the intrinsic clotting system
- Activated by direct contact with endotoxins, collagen, basememnt membrane i.e. any NEGATIVELY charged surface

Triggers:

  • Kinin system
  • Clotting cascade
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Outline the Kinin System.

A

1) Activated Hageman Factor (XII) converts Prekallikrein to Kallikrein
2) Kallikrein:
- Amplifies activation of Hageman Factor
- Cleaves kininogen to form kinins including bradykinin
- Converts plasminogen to plasmin
- Converts C5 to C5a, a chemoattractant for luekocytes
- Increases cell adhesion molecule expression

25
What is bradykinin? What is the function of bradykinin?
Bradykinin= a short-lived vasoactive peptide - Increases vascular permeability - Dilates blood vessels - Contracts non-vascular smooth muscle - Causes pain *Note that bradykinin is inactivated by plasma kininase
26
What is thrombin?
- Thrombin is a protease that cleaves fibrinogen to generate insoluble fibrin - It is the link between inflammation and coagulation
27
What is the function of thrombin?
Binds protease-activated receptors (PARs) that - Mobilize P-selectin - Produce chemokines, PAF, and NO - Stimulate enothelial adhesion molecule formation - Induce COX-2 and production of prostaglandins - Induces changes in endothelial shape
28
What is plasmin?
Protease formed by cleaving plasminogen by kallikrein or plasminogen activator released by endothelium and leukocytes
29
What is the function of plasmin?
Lyses fibrin clots - Activates Hageman Factor (XII) - Cleaves C3 to C3a - Degrades fibrin to form fibrin split products that increase vascular permeability in skin and lung
30
What is Arachidonic acid?
- Normally bound to cell membrane phospholipids | - Released by the action of cellular phospholipases
31
What are the two key pathways that stem from AA?
1) COX | 2) LOX
32
Outline the COX pathway.
COX converts AA into protaglandin intermediates that form several inflammation related products including: - Thromboxane A2 (TXA2) - Prostacyclin (PGI2) - PGE2 - PGD2, PGF2a, PGE2
33
What is TXA2 & what is its function?
Thromboxane A2= potent platelet aggregator and vasoconstrictor
34
What is PGI2 & what is its function?
PGI2= protacyclin, a vasodilator and inhibitor of platelet aggregation
35
What is the function of PGD2, PGF2a, and PGE2? What is unique about PGE2?
All three cause vasodilation and potentiate edema - pGE2= also sensitizes skin to painful stimuli and plays a role in cytokine induced fever
36
What is the mechanism of action of aspirin? What is the mechanism of action of glucocorticoids?
Aspirin & NSAIDS= inhibits COX-1 & OCX-2, reducing platelet aggregation & vasoconstriction Clucocorticoids= inhibit phospholipases and the release of AA
37
Outline the LOX pathway.
Lipoxygenase converts AA into HPETE compounds, and then leukotrienes & lipoxins
38
What is the function of Leukotriene B4 (LTB4)?
Potent chemoattractant causing - neutrophil aggregation & adhesion to endothelial cells - generation of ROS - release of lysosomes
39
What is the function of Leukotrienes C4, D4, E4?
Cause intense vasoconstriction, bronchopasm & increase vascular permeability *Allergic reaction
40
What are lipoxins?
- Endogenous negative regulators of leukotriene action | - Principal actions are to inhibit leukocyte recruitment and the cellular activities of inflammation
41
What is the function of Lipoxin L4 & B4?
Inhibition of neutrophil adhesion to endothelium and neutrophil chemotaxis
42
What is PAF?
Platelet Activating Factor - Causes platelet aggregation - Has multiple inflammatory effects
43
What is the function of PAF dependent on?
Concentration- dependent: - Low= vasodilation & venular permeability - High= vasoconstriction & bronchoconstriction
44
What are cytokines?
Polypeptides that function as cellular hormones or locally acting cell-to-cell mediators
45
What are chemokines?
Cytokines with strong chemotactic properties
46
What cells produce IL-1 & TNF-a?
Activated macrophages
47
What are the functions of IL-1 & TNF-a?
These are two cytokines that work synergistically to mediate inflammation, including: - Acute phase reactions - Endothelial effects - Fibroblast effects - Leukocyte effects
48
What are the acute phase reactions produced by IL-1 & TNF-a?
- Fever - Affect sleep and appetite - Acute phase proteins - Neutrophilia - Hemodynamic effects in shock
49
What are the endothelial effects of IL-1 & TNF-a?
- Increased expression of leukocyte adhesion molecules - Stimulate PGI synthesis - Increase procoagulant activity - Increased production of IL1, IL-6, IL-8, and PDGF
50
What Fibroblast effects of IL-1 & TNF-a?
- Increases proliferation, collagen synthesis, and PGE synthesis - Increases protease and collagenase production
51
What are the Leukocyte effects of IL-1 & TNF-a?
Increased cytokine secretion (IL-1 & IL-6)
52
How are chemokines classified?
Classified according to conserved cysteine residues in the protein
53
What is the difference between C-X-C or alpha chemokines, C-C or beta-chemokines, C or gamma chemokines, and CX3C?
Alpha= act primarily on neutrophils e.g. IL-8, which is important for neutrophil chemotaxis Beta= attract monocytes, eosinophils, basophils, and lymphocytes, but NOT NEUTROPHILS Gamma= specific for lymphocytes CX3C= attractant for monocytes and T-cells
54
What is NO? List the functions of NO.
Nitric Oxide - Soluble free radical gas that is produced by: macrophages, endothelium, and some neurons - Strong vasodilator - Reduces platelet aggregation - Microbicidal
55
What are ROS?
Reactive Oxygen Species released from neutrophils & macrophages
56
What is the function of antioxidants?
Protection from free radicals
57
What are neuropeptides?
Substance P & Neurokinin A
58
What are the biological functions of substance P?
- Transmission of pain signals - Regulation of blood pressure - Increasing vascular permeability