Inflammation Flashcards
1
Q
what is the 1st cell to become activated?
A
- mast cells
- granules = histamine and heparin
- after 30 min, leukotrienes
2
Q
name the 3 major components of acute inflammation
A
- vascular dilatation: relaxation of vascular smooth muscle leads to engorgement of tissue with blood (hyperemia)
- enodthelial activation: increased endothelial permeability allows plasma proteins to “leak” into tissues; expression of adhesion molecules on the endothelial surface causes neutrophil adherence; production of factors that cause vascular dilatation
- neutrophil activation and migration: expression of complementary adhesion molecules; increased motility - emigration from vessels into tissue
3
Q
name the inflammatory chemical mediators
A
- complement components C5a and LTB4
- neutrophils migrate towards higher concentrations of these agents (chemotaxis)
- leads to early formation of exudate
- neutrophil, plasma, fibrinogen
4
Q
name compounds involved in vasodilation,
A
- vasodilation
- histamine
- bradykinins
- prostaglandins
- NO
- endothelial activation
- serotonin
- histamine
- bradykinin
- neutrophil activation and migration
- C5a
- LTB4
5
Q
describe opsonization
A
- neutrophils play an important role in destruction of microorganisms; phagocytosis of organisms is promoted by a coating of immunoglobulin and complement factors called opsonization
6
Q
describe suppurative or purulent inflammation
A
- the exudate in purulent inflammation is rich in neutrophils; this commonly results from bacterial infection
- pus = semi-liquid containing neutrophils, fluid and necrotic tissue
- bacteria that promote purulent inflammation = pyogenic bacteria
7
Q
describe fibrinous inflammation
A
- the exudate in fibrinous inflammation has a high plasma protein content
- fibrinogen, a plasma protein, is converted to fibrin and deposited in tissues
- usually associated with serous membrane-lined cavities (pleural, pericardial, peritoneal)
8
Q
contrast the 2 images
A
left = suppurative/purulent inflammation
right = fibrinous inflammation
9
Q
describe serous inflammation
A
- the main tissue component is accumulation of fluid with a low plasma protein and cell content (transudate)
- transudate: specific gravity <1.012 or protein content <25g/L
- exuate: specific gravity >1.02 or protein content >25g/L
10
Q
name the 4 outcomes of acute inflammation
A
- resolution
- healing by fibrosis
- abscess formation
- progression to chronic inflammation
11
Q
describe resolution
A
- complete restitution of normal tissue architecture and function; can only occur when the CT framework is intact and the tissue has the capacity to regenerate
- neutrophils and necrotic tissue are removed by phagocytosis (macrophages) which leave the tissue via the lymph drainage
- ex: following pneumonia, recovery from sunburn
12
Q
describe healing by fibrosis
A
- occurs with substantial damage to CT framework and/or in tissues that lack ability to regenerate specialized cells
- necrotic debris and acute inflammatory exudate are first removed by macrophages
- the defect becomes filled by ingrowth of granulation tissue (organization)
- granulation tissue is gradually replaced by collagen to form a fibrous (collagenous) scar
- structural integrity is re-established
13
Q
describe abscess formation
A
- acute inflammatory response fails to destroy/remove the cause of tissue damage; continues, usually with a component of chronic inflammation
- acute inflammation progresses producing liquefaction of tissue to form pus
14
Q
describe chronic inflammation
A
- cells in chronic inflammation:
- lymphocytes
- macrophages
- plasma cells
- eosinophils
- fibroblasts
- FMLEP
15
Q
describe a granuloma
A
- granulomas form when the immune system attempts to wall off substances that it perceives as foreign but is unable to eliminate
-
it is a collection of macrophages in an organized formation
-
they fuse to form multinucleated giant cells (Langerhans giant cell)
- reffered to as epithelioid
-
they fuse to form multinucleated giant cells (Langerhans giant cell)
