Acute Inflammation Flashcards by C K

Key Features of acute inflammation

edema
dilated vessels
infiltration by activated neutrophils (early) and macrophages (later

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systemic effects of acute inflammation

fever
neutrophilia
fatigue
Loss of appetite
increased acute phase proteins in blood

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outcomes of acute inflammation

resolution
healing by fibrosis
abscess formation
chronic inflammation

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important mediators in vasodilation

histamine
prostaglandins
NO

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important mediators in increasing vascular permeability

serotonin
histamine
C5a
C3a
leukotrienes

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important mediators in leukocyte activation and chemotaxis

C5a
leukotriene B4
bacterial products/chemokines

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What is inflammation?

universal response to tissue damage by harmful stimuli:
mechanical trauma
tissue necrosis
infection

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What is the purpose of inflammation?

destroy (or contain) the damaging agent
initiate repair processes
return the damaged tissue to useful function

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Define hyperemia

Relaxation of vascular smooth muscle leads to engorgement of tissue with blood in the first phase of acute inflammation

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Which adhesion molecules are expressed by activated neutrophils to make contact with endothelial cells?

integrins and selectins

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What is the regular lifespan of a mature neutrophil?

3 days

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How do neutrophils kill bacteria and insulting agents before undergoing apoptosis?

Generate respiratory burst to produce hydrogen peroxide and other reactive oxygen species

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How are dead neutrophils cleaned up?

by macrophages that arrive by 2nd/3rd day after injury

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Which plasma proteins are involved in acute inflammation?

C5a
C3a
immunoglobulins
fibrinogen and fibrin

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How long does acute inflammation last?

hours to days depending on the type and severity of the tissue damage

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What is pavementing?

neutrophils lining up at the periphery of a vessel waiting to extravasate

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What is the typical acute inflammatory exudate made of?

water
proteins (fibrin)
neutrophils

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What are the mediators of increased vascular permeability?

vasoactive amines
serotonin (5-hydroxytryptamine (5-HT)) 
histamine
C5a and C3a 
leukotrienes C4, D4, and E4
platelet activating factor (PAF).

Describe Suppurative (purulent) inflammation

rich in neutrophil leukocytes

due to of infection by bacteria

What is pus?

mixture of neutrophils (viable and dead), necrotic tissue, and tissue fluid in the acute inflammatory exudate

What is an abscess?

a circumscribed collection of semi-liquid pus

What is the cause of destruction of tissue in acute inflammation?

release of neutrophil lysosomal enzymes

destruction by bacteria

What are pyogenic bacteria?

Bacteria which produce purulent inflammation

What are examples of pyogenic bacteria?

Staphylococci
Streptococcus pyogenes 
Streptococcus pneumoniae
E. Coli 
Neisseria meningitidis
Neisseria gonnorrhoeae

What is contained in the exudate of fibrinous inflammation?

high plasma protein content (fibrinogen converted to fibrin)

Where is fibrinous inflammation usually found?

membrane-lined cavities such as the pleura, pericardium and peritoneum, where the fibrin strands form a mat-like sheet causing adhesion between adjacent surfaces

What is transudate?

fluid with a low plasma protein and cell content (transudate = specific gravity

What is an exudate?

specific gravity >1.020 and protein content >25 g/L

When is a transudate commonly seen?

in the skin in response to a burn

What are the three big cytokines involved in acute inflammation (and mediates fever)?

interleukins 1 & 6, tumour necrosis factor (TNF) and prostaglandins

What are the four end outcomes of acute inflammation?

resolution healing by fibrosis/scar formation abscess formation chronic inflammation

Describe resolution

complete restitution of normal tissue architecture and function that can only occur if the CT framework of the tissue is intact and the tissue involved has the capacity to replace any specialised cells that have been lost

Describe healing by fibrosis

substantial damage to the CT framework and/or the tissue lacks the ability to regenerate specialised cells defect becomes filled by ingrowth of a specialised vascular connective tissue called granulation tissue

What is the two types of granulation tissue and what are their differences?

vascular granulation tissue - proliferating leaky capillaries, fibroblasts and inflammatory cells fibrous granulation tissue - vessels regress, collagen laid down and is remodelled into orderly pattern to withstand tensile stresses occurs for many weeks

What is healing by primary intention?

wound edges are in close apposition and the actual defect is minimal, healing occurs quickly with a small amount of granulation tissue and is termed

What is healing by secondary intention?

large tissue defect filled with blood clot and a variable amount of tissue debris. In this case, organization and filling of the defect by granulation tissue will take longer

What is a feature of inactive fibrobalsts (after they have finished laying down collagen?)

small, condensed nuclei

What does healing of the skin or mucous membrane require

epithelialization of the surface by proliferation of epithelium at the edges of the defect

What bacteria will cause an abscess formation?

pyogenic bacteria

What is liquefaction?

Liquefactive necrosis of the cells inside an abscess that is basically pus

What is an abscess?

chronic inflammation surrounding acute inflammation (dead neutrophils and viable bacteria forming pus in the middle)

Are the bacteria inside the abscess alive?

Yes

What is a chronic abscess?

an abscess encapsulated by granulation and fibrous tissue