Inflammation

Question 1

what is the 1st cell to become activated?

Answer 1

• mast cells
• granules = histamine and heparin
• after 30 min, leukotrienes

Question 2

name the 3 major components of acute inflammation

Answer 2

1. vascular dilatation: relaxation of vascular smooth muscle leads to engorgement of tissue with blood (hyperemia)
2. 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
3. neutrophil activation and migration: expression of complementary adhesion molecules; increased motility - emigration from vessels into tissue

Question 3

name the inflammatory chemical mediators

Answer 3

• complement components C5a and LTB4
  
  • neutrophils migrate towards higher concentrations of these agents (chemotaxis)
• leads to early formation of exudate
  
  • neutrophil, plasma, fibrinogen

Question 4

name compounds involved in vasodilation,

Answer 4

• vasodilation
  
  • histamine
  • bradykinins
  • prostaglandins
  • NO
• endothelial activation
  
  • serotonin
  • histamine
  • bradykinin
• neutrophil activation and migration
  
  • C5a
  • LTB4

Question 5

describe opsonization

Answer 5

• neutrophils play an important role in destruction of microorganisms; phagocytosis of organisms is promoted by a coating of immunoglobulin and complement factors called opsonization

Question 6

describe suppurative or purulent inflammation

Answer 6

• 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

Question 7

describe fibrinous inflammation

Answer 7

• 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)

Question 8

contrast the 2 images

Answer 8

left = suppurative/purulent inflammation

right = fibrinous inflammation

Question 9

describe serous inflammation

Answer 9

• 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

Question 10

name the 4 outcomes of acute inflammation

Answer 10

• resolution
• healing by fibrosis
• abscess formation
• progression to chronic inflammation

Question 11

describe resolution

Answer 11

• 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

Question 12

describe healing by fibrosis

Answer 12

• 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

Question 13

describe abscess formation

Answer 13

• 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

Question 14

describe chronic inflammation

Answer 14

• cells in chronic inflammation:
  
  • lymphocytes
  • macrophages
  • plasma cells
  • eosinophils
  • fibroblasts
• FMLEP

Question 15

describe a granuloma

Answer 15

• 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

Question 16

contrast Langerhan giant cells and foreign body giant cell

Answer 16

• Langerhan giant cell: surround bacteria, organism, protozoa
• foreign body giant cell: surround foriegn object (glass splinter, suture)